N O P Q R S T U V W X Y Z

• Non Maskable Interrupt (NMI).

This Interrupt is tied directly to a special NMI pin on the CPU. It is used to immediately deal with catastrophic events.

• Non Windows Application.

An app that is designed to run with DOS but not specifically with Wins. By default, when a DOS app is executed it appears as a full DOS screen. You can press "ALT + Enter" at anytime to reduce the screen to a window (in Enhanced Mode only) or what is often referred to as a DOS Window. This can be moved and sized like a normal window. Since the DOS app. is not a Wins app, the control menu contains settings that can be adjusted while the DOS app is running

• Object

Any piece of info, created by using a Wins based app, that can be linked ( linked object, or embedded (embedded object), in another document.

Object Orientated Programming (OOP) special feature

• Object Linking and Embedding (OLE).

OLE is a major feature of Wins and is therefore also a major feature of many Wins apps. Linking and embedding are two different ways of exchanging info between individual 'tools' in a Wins app or between different apps that support OLE. Once you have linked or embedded info it becomes an object whatever form of document it is. Apps that support OLE fall into two categories. Apps whose objects can be embedded or linked into other docs are called servers. Apps that can accept embedded or linked objects are called clients. Some apps may be both a server and a client. Others are only one or the other. Some apps are OLE containers or clients which means OLE objects can be pasted in (these apps can also act as servers). Some apps are purely OLE server apps which create OLE objects for pasting into an OLE container. Some OLE objects are not intended as printable pictures and can be anything from macro buttons to sound objects.

A complex specification, the technology being developed by MS, that describes the interfaces used for tasks, such as embedding objects created by one app within docs created by another, performing drag and drop data transfers (e.g Wins File manager) within or between apps, and much more. It could be thought of as a technique for using the same object (sharing info) across apps.

Embedding is the process by which an 'object' created using app 'A' is inserted into a document created using app 'B' such that when embedding the object in the app 'B' doc you also embed all the info needed to make changes to that object so that you never have to leave app 'B' to edit or modify the object. Because the embedded object maintains 'ties' or 'links' with app 'A' in which it originated, simply by 'double-clicking' the object you can open app 'A' from within app 'B' and so edit the object. (nb the term 'object' is used as a term for the component being embedded.)

Ver. 1.0 was created for placing objects inside docs created by other apps. OLE 2.0 expanded to include more than just linking and embedding of objects but the recognised name was retained.

A way to transfer and share info between apps so that apps contain components from various other source apps. OLE enables apps to share data by embedding an item, sometimes a graphic object, within a document. The 'object' within the app is 'linked' with a different app. When the object is selected the Server App (Client /Server apps) is launched in order to edit the object.

• Object Packager.

A tool used to create a 'package' and then insert it into a doc. A package is an icon that represents an embedded object or a linked object. To create a packaged object with 'Object Packager', the contents must be copied to the Clipboard and become the 'package' when inserted into a doc. The contents of the package can be created using any app, not only one that supports Object Linking and Embedding. Regardless of the package contents, a package can only be inserted into a doc that has been created using a client app?. You can only insert a package into a client app.

• One to many, One to one

Also called a 'parent child' relationship, a collection between two data entities in which there may exist one corresponding value in the primary key of one DB file or table, to many identical values in the foreign key of another table. For example the relationship of states to cities implies a state may have many cities. In the case of One to One the relationship could be a customer name to Internet address.

• Open DataBase Connectivity (ODBC.)

A standard promulgated by MS that allows DBs created by various DB management progs to be accessed using a common interface, independent of the DB file format. Using ODBC you can write an app. that uses the same code to read records from a dBASE file or from a 'FoxPro' file. Internally, ODBC drivers use a form of SQL to carry out DB operations.

Provides a standard Applications Programming Interface for accessing multiple DB file formats via replaceable file drivers and Client / Server support.

ODBC Administrator

A re-distributable MS app for adding, maintaining or deleting individual ODBC drivers within a system. Usually located in the Wins\System directory, the executable filename is ODBCADM.exe.

ODBC driver

A driver library containing the individual functions supporting standard ODBC calls for a particular file format.

• Objects : definition

Objects may be viewed initially as 'black boxes' or abstractions which allow us to define what they should be capable of doing without worrying about the implementation. The study of object orientated analysis and design is a subject in its own right. Objects are specified through a class description which is a prescription of what the object has in it and the way one may access it. Objects encapsulate data and functions (or methods), the intention being to provide users of the objects with a 'package' which will allow them to build useful systems. Access to the objects' data members is generally restricted (the user 'interface') through access functions. Access to the class members is controlled through access specifiers, thus providing an important level of control and security.

The default access to a class object is 'private' but C++ provides for two other specifiers, namely 'public' (for user interface) and 'protected' used only when creating derived classes. Objects can be extended by a process of inheritance allowing the user to create new or more specialised objects.

Various categorisations have been loosely made for objects, namely :

Data Objects

Starting at the bottom, these are 'lumps' of data which could be a paragraph of text or a block of spreadsheet cells. Apps are unconcerned since it is the OS that manages data objects, which could be referred to as simply files.

Application Objects

Paragraph or cell blocks from the apps point of view. This is raw material for OLE 2.0 and although there might be mapping of app objects to data objects OLE 2.0 for one defines a new data object storage model all of its own within conventional files.

Desktop Objects

Appearing on the 'desktop' they represent progs, files, program objects or whatever else the GUI decides they should represent. e.g OLE.

Programming Objects

These sit below apps and 'desktops'. The emphasis is on producing 'lumps' of code that are not only reusable in a variety of apps, but can also produce variants of themselves under certain conditions.

On a different note for users, terminology is the main obstacle to understanding what is really going on and none of the categories of objects described necessarily has any connection with any of the others, or with anything approaching real life. Objects could be seen to make things easier for developers but confuse users. It follows that companies like Borland need only do a particular proging job once and in-house business developers can produce progs by 'bolting' together pre-defined code objects.

• Optical Character Recognition (OCR.)

A technology that converts characters in a bitmapped image into ASCII text. OCR is frequently combined with scanners for scanning docs into a PC and converting the resulting info into textual data.

• OS/2 (Operating System 2)

IBM's O>S was technically superior to Wins in its evolution but few apps were written for it due mainly to bad management. OS/2 came out at a time when users were unwilling to leave DOS for something completely different. The real need for a fully protected, secure environment did not exist, and when it did, people wanted the familiarity of the DOS prompt if they could keep it. Wins offered this, it ran on top of DOS and users could start Wins, run it for a while, then go back to their old familiar standby.

Wins 3.0 was released in May 1990. Running in protected mode it offered more memory than previous versions and better inter-process protection, plus it was sitting on the familiarity of 'old' DOS. Very quickly Wins became the common O>S on many users m/c's and IBM-compatible users were now ready to move to a graphical environment, Wins 3.0 offering the memory access and protection necessary for such an environment to be palatable.

The success of Wins Ver. 3.0 created conflicts between IBM and MS who had been working together on OS/2. Yes, MS had dual interests and Wins was clearly the marketing champ so by Sept. 1990 the joint development agreement between the companies broke down. IBM focused on OS/2 and MS focused on Wins. OS/2 Ver 2.0, a fully 32 bit O>S was eventually shipped in spring 1992 in small quantities but IBM did not have the skill that MS does in convincing independent software vendors to write apps for its environment and sadly to this day 32-bit OS/2 progs are quite scarce. It is impractical to ask developers to learn a new environment every couple of years or so and it was tough enough for DOS developers to tackle the intricacies of Wins. Telling them to then shift to the OS/2 'presentation manager' was ridiculous. Even though OS/2 came out with the features that people want today long before Wins NT was out, Wins was entrenched in corporate America first. Finally upgrading to NT from 3.1 is easier than learning the new OS/2.

• Page Addressing

Since Page Memory is small, only a small address is needed. A short address can be used with a 'base plus displacement' addressing scheme. The high order address byte can be stored in the CPU while the low order address byte is specified by a direct addressing instruction. This works well when most of the addresses are located near each other (on the same page) so they have the same high order byte. In Paging, one register is used to hold the Page Address and there must be instructions to manipulate the register contents, such as increment or decrement commands,

• Page Frame.

This is the area of RAM, usually 64kb, between A000 and F000 Segment Address, reserved for swapping EMS Pages into (page = 4KB.) A Page is a Segment of a computer prog that has a Virtual Address and can be located in Mem. or HDD. A Page can be moved into Mem. by the O>S whenever the instructions of that sub-division or Page need to be performed. A Prog can be divided into Pages in order to minimise the total amount of Mem. allocated to the Prog. A Page can be accessed by its owner Prog only while it is 'swapped' into the Page Frame.

• Partition.

A logical portion of Memory on a HDD that acts as a separate unit. A single HDD can be divided into several Partitions (using MS-DOS) where each Partition acts as if it were a separate physical disk. You could have different O>S's in each Partition, but the CMOS would need setting to the required Partition for 'Boot Up', if the current setting was not the one required. All HDD have at least one Partition, Partitions can be used to divide a large HDD into separate areas which are called Logical Drives. Each Logical Drive is assigned a Drive letter, just as though it were a separate HDD.

Info specifying the disk location and length of each Partition on the disk is stored in the Partition Table. The DOS Command FDISK is used to create Partitions on a HDD, and destroys all data on the disk.

• Partition Table.

A HDD is divided into areas called Partitions and refereed to by Logical Drive names (C:\, D:\, E:\ etc.). The Partition Table contains info about each Partition on a particular physical HDD such as which Sectors belong to which Partitions and it resides in the System Area of the disk. A disk may be Partitioned to contain several different DOS Drives of various sizes, or Drives for different O>S, such as OS/2 or XENIX.

• Paste Special command

EDIT / PASTE 'pastes' a copy of the contents of the Wins clipboard on to the current page. The Wins Clipboard can contain different formats of the same object (e.g Picture, Bitmap, OLE). PASTE (Ctrl+V) will always use the correct format for the app if it is available. EDIT / PASTE SPECIAL allows a choice of format to be pasted from Wins Clipboard. PASTE inserts info without creating a link, PASTE SPECIAL / LINK creates a link with the app from which it originated. (See Linked Object) With a link, you can choose to update the data automatically, or only when you specify. Also choose to dispay the pasted and / or linked info as an icon in the doc. You can click the icon to display the info or switch to the source doc if required to make changes to linked info. (Same as object packager ?) If the Paste Link option is dimmed you have copied info from a doc that has not been saved.

• Path Statement

A statement listing directories where DOS automatically searches for progrm files when it cannot find requested files in the curent directory.

• Plug and Play (P'n'P)

The technology that lets Wins 95 automatically detect and configure most of the adapters and peripherals connected to a PC. A fully PnP enabled PC requires three components; a PnP BIOS, PnP adapters and peripherals and a PnP O>S. Adding a PnP compliant CD Rom drive, HDD, monitor, printer or other device to a PnP P.C. requires little more than making the physical connection. The O>S in conjunction with PnP logic present in the BIOS and in the device itself, handles the IRQ settings, I/O addresses and other technical aspects of the installation to ensure that the drive does not conflict with other installed devices.

• Port

A Port is an interface through which data passes to and from the CPU, the 8086 has 64k Ports. The System Bus is like a party line which is used in common by every part of the PC that is assigned a Port Number. The designers of any Micro decide which Port Numbers to use for various purposes and the circuit elements of the PC are wired to respond to those numbers. When the CPU needs to talk to one circuit part or another, it signals the Port Number on the Bus, and the appropriate part responds. Ports are the mechanism the CPU uses to talk with other parts of the PCs circuitry. Ports are used to connect PCs to external devices such as printers, monitors and modems.

• Power On Self Test (POST).

This is performed by the Basic Input Output System during the 'boot-up' process. The BIOS performs tests on the Complementary Metal Oxide Semiconductor battery, CMOS configuration, Base Mem., Disk Controller and Clock. The results of the POST Test are then stored in CMOS for later reference.

• Program File

An executable file that launches an app. Extensions are EXE, PIF, COM or BAT. E.g Progman.Exe is the prog file to launch Wins Program Manager. Progman.ini is an INItialisation File that stores info about what should appear in the Program Manager window when you run the Program Manager.

• Program Information File (PIF, file extension = .PIF).

A binary file in which Wins stores configuration info about a DOS prog. Every PIF file should have a corresponding * .EXE or app file associated with it. The PIF file gives info about the DOS app. such as the path to the executable file, the amount of mem. the prog requires so Wins can work best with it. If a DOS prog does not have its own PIF, Wins runs the prog using settings in default.pif.

• Program Segment Prefix (PSP).

A small area of Mem. associated with each running Prog, which contains info used by DOS to help run the Prog. When DOS loads a Prog, it sets aside a 256 byte block of Memory.

• Protected Mode

Came in with the x286 and applies through to the Pentium, being one of the two main states of processing (compare with Real Mode). It provides the capability of multitasking, by allocating Memory to various processes running concurrently, protecting Data Segments in use by one Prog from access by another, so that memory used by one process does not overlap memory used by another process. Protected Mode maps areas of the CPU as Virtual 8086 processors, and assigns Tasks to them, up to 4GB of Memory can be addressed when in Protected Mode.

• DRAM (Dynamic RAM) & SRAM (Static RAM)

DRAM stores each bit of info in a 'cell' composed of a capacitor and a transistor. Because the capacitor in a DRAM cell can hold a charge for only a few milliseconds, DRAM must be continually refreshed in order to retain its data.

SRAM requires no refresh and delivers better performance offering faster memory access times as no refresh cycle is necessary ( a critical element in a PC's performance.) However, it is physically bigger containing more electrical components less densely packed on the chip, consumes more power and is thus more expensive to manufacture than DRAM. A large Main Mem. based wholly on SRAM would be prohibitively expensive. Therefore the most common use for SRAM is to 'cache' data travelling between the CPU and RAM subsystem (Main Mem.) populated with DRAM, this boosts performance by reducing the number of DRAM accesses required. SRAM stores small blocks of system DRAM to create the illusion that all system Mem. is available at the high speed of cache mem. The circuits that manage the filling of the cache from slower DRAM is called a Cache Controller.

• Real Address Mode

A Mode in x286/386 CPUs where physical Memory is a contiguous array. The Selectorportion of the pointer is interpreted as the upper 16 bits of a 20 bit address, and the remaining 4 bits are set to zero. This is compatible with the 8088 and 8086. Segmentsare 64k in size and may be read, written or executed.

• Real Mode.

The operating mode of DOS and technically one of Wins that allows the least flexibility for Memory Management, when compared with later developments. This Mode is used by those m/cs that have an 8088 or 8086 CPU and associated architecture or systems that have less than 1MB of RAM (as only 1MB may be addressed). It allows only one app to run at a time with free access to Memory and all I/O devices.

Allows an x286 > Pentium to emulate an 8086 and run only one process at a time, the Intel CPU cannot multitask in real mode. It is suggested not to use this mode with Wins (if it can be at all) as performance is severely limited. When you use DOS the CPU is working in Real Mode and is the only Operating Mode supported by DOS. When x286 > work within DOS's 1MB address limit, they work in Real Mode.

• Read Only Memory (ROM, EPROM, EEPROM).

The generic term for memory that can be read from, but not written to. The BIOS is typically contained in ROM and this offers two advantages; the code and data in the BIOS need not be reloaded each time the PC is started, and they cannot be corrupted by wayward apps that write into the wrong part of memory. Some forms of ROM can be rewritten by applying higher than normal voltages to the inputs. An EEPROM (Electrically Erasable Programmable ROM ) can be updated like a piece of software. An EPROM (Erasable Programmable ROM) can be erased by high intensity UV light and then rewritten.

A type of Memory chip that has Prog Instructions and Data permanently stored in it. The System BIOS resides in a ROM (System ROM). These are the Routines that interact directly with the Hardware Devices in your PC. System ROM is most often associated with the type of PC that you have. Some 'generic' m/cs implement popular BIOSes and are therefore more often associated with the BIOS type than the actual manufacturer. There are also ROM's that are in Video Controllers, hard disk Controllers, network cards, the SCSI bus subsystem has one, and even the printer.

• Reduced Instruction Set Computing (RISC.)

A CPU architecture that favours the speed at which individual instructions execute over the robustness of the instruction set. The PowerPC architecture in 'SUN' Microsystems is just one example. See more

• Run-Time & Run Time Library (RTL).

The time when code is running. During run-time a developer can interact with the app as a user would. In contrast, during development time, the app is built. The library is a Dynamic Link Library file providing essential support for basic app functions.

Basically, it enables copies to be made of developed apps and distributions of said apps to other users who do not own full copies of the original prog version (*.EXE file).

The following description is one advertised by the Alpha Software Corporation with their 'Alpha Four Run-Time Prog' developed for their DB users of version 4 and later versions.

Who benefits

The commercial DB app developer can earn revenue from his apps more quickly and easily.

The corporate department head or MIS manager can easily develop many different stand-alone or multi-user custom solutions for an entire company without proging, and distribute the apps to his end-users more cost-effectively than by any other means. They are also claimed to run 3 to 10 times faster than apps built with Wins DBs.

The private entrepreneur can develop, make copies and distribute custom Alpha Four DB apps to other people who do not own a full copy of the Alpha Four DB prog, in an easy, fast and cost effective way as in the above cases.

How is it used ?

The app is created in the usual way using the full prog copy and all its components such as custom reports, forms and Power-Scripts. The end-user is then provided with copies of all the files needed to run the Alpha Four app that has been created such as the data, app, forms, browse table, reports, index and Power-Script files.

The A4RT.EXE (Alpha Four Run-Time Prog file) is included which acts the same as the A4.EXE file but with a few very important exceptions such as creating an index or a new DB, using any SET commands, creating / editing field rules and using any of the 'Script' menus.

No complicated and time consuming proging languages, compilers, linkers and debuggers are required as with most other DB app development tools.

'Alpha Four' Ver 4 Run-Time Program Utilities

þ Create .EXE files to start the apps. This allows the end-user to 'launch' his Run-Time app smoothly and elegantly, either by typing a simple command at the DOS prompt or setting up a 'program item' in the Wins Program Manager and double-click on an icon.

þ Encrypt the apps. Once the app file is encrypted there is no worry of a novice user inadvertently altering the app. The author of the distributed app can be guaranteed to be the only one who can edit, 'upgrade' or 'add value' to a previously encrypted Run-Time App.

þ Create trial versions of the app. Useful for marketing, these will behave in exactly the same way as the full working versions, except the DBs and sets will be limited to only 100 records. This gives potential clients an opportunity to test the app before purchasing the full-working version.

þ Strip or change drive prefixes in various app files. This ensures that apps are easy to install on other m/cs, even if the drive mappings and directory structures are different to the authors.

þ Create installation progs. The author can create his own custom set-up progs to make installation of the Run-Time apps easy for him and the end user. Large files can be split among multiple diskettes.

Business Opportunity

Run-Time Progs give unlimited distribution rights to the apps, so the investment in the Alpha Four Run-Time Prog is a one-time cost only. If you are a corporate developer, it gives you the lowest cost way to distribute an unlimited number of RDB apps within your firm.

Alpha Software make a number of Run-Time packages available including :

Single-User, Unlimited Distribution Run-Time.

5 Node Multi-user, Unlimited Distribution Run-Time.

20 Node Multi-user, Unlimited Distribution Run-Time.

Unlimited Node Multi-user, Unlimited Distribution Run-Time.

All the above are progressively more expensive but for a one-time fee, the last three needing a network and server.

• Sector.

The basic unit of data on HDD & FDDs, and the smallest unit of disk space that can be read or written at a time. Typically 512 bytes or 1024 bytes.

• Segment.

A part of a Routine short enough to be sorted entirely in the internal storage of a PC, yet containing the codes necessary to call in and jump to other Segments. A Segment can be placed anywhere in Memory and addressed relative to a common origin.

• Segment Registers

Registers that extend the addressability of the Memory beyond the instruction Word limit (length). Extensions beyond the Word Length are accomplished by adding additional bits to the Address. Special instructions maybe dedicated to the manipulation of these Registers.

• Segmented Memory Model

One of two distinct Memory Models, the other is based on 32-bits. Wins 3.x provides 16-bit app support primarily, i.e 16-bit registers (65,536 bytes). Wins cannot access all the Memory using one register, so it uses a Segmented Memory Model, which uses two registers combined to access all the Memory in the PC. This brings extra work to the programmer who has to worry about a Segment Register and an Offset Register.

So why use only the Segmented Model for Wins 3.x and not a 32-bit system ? Firstly, the x286 did not provide Flat Memory Model support (there would have to be backward compatibility for the number of x286s around or further complicate things with two versions if Wins) and secondly Wins 3.x 'sits' on DOS, which uses 16-bit code. Wins 3.x is already juggling with DOS without further complicating the issue. Therefore Wins 3.x is a 16-bit O>S.

A Seg. Memory Model uses two 16-bit registers to hold an address. In Real Mode, the CPU uses a Segment and an offset, which are combined to create a 20-bit address (1MB) for the 8086 or a 24-bit address for the x286 (16MB). The bottom line for the app is that the app and not the O>S has control over the Mem it uses.

• Server

A 'remote' PC providing data storage or services to other physically linked PCs. A PC on a network that is used to share resources, such as directories and printers. A server can also function as a PC within a Workgroup.

• Shell.

An interface between you and the O>S, whether it is Wins, Dos, Unix or otherwise. Shells allow you to launch Progs and manage files to varying degrees. Wins Program Manager is a Graphical User Interface (GUI) that acts as a Shell. A Wins app could be made to act as the shell showing the 'face' of the app on start-up if a command is set in System.ini

• Slack.

The amount of space that a file takes up on a drive, which is often more than the actual size of the file. This difference is the result of the Cluster size created by the particular Drive Partition. That is, the minimum amount of room required by a file, no matter how small, is determined by the size of the Clusters in use on that said Partition, with the Cluster size being determined by the size of that Drive Partition.

A Drive Partition between 16 & 127 MB in size uses Clusters of 2k, with each file created on that Drive taking up a minimum of 2k in space. Drive Partitions from 128 to 255 MB contain 4k Clusters, so every file on that Drive consumes 4k of space even if the File is considerably smaller. Larger Partitions use even larger Cluster sizes, with the minimum amount of space required to store a file increasing accordingly. Data from previous files may remain in the Slack Area.

• Source document

The doc from which a linked object or embedded object originates.

• Standard Mode.

An operating mode of Wins that originally allowed apps to access Extended memoryeasily. The only reason for the existence of Standard Mode is the x286 and it enabled Wins to run on a chip that only provided access to 16MB of RAM max., and only needed 1MB as a minimum. It is one of the two modes in which Wins 3.1 runs (Wins for Workgroups 3.11 and newer versions will not.) Chosen automatically for Wins if your system has an x286 CPU, or if you have a better CPU (the superior Enhanced Modecame in with the x386 >) but less than 2MB of Main Memory.

In Standard Mode you can not Multitask Wins apps, only Task Switch between them which essentially means that you can open as many apps as memory will permit but only the foreground task will actually do anything. To run Standard Mode on a x386 class m/c, type "win/s". If you run exclusively in one mode or other (Standard or Enhanced) you can safely delete the files used only by the other mode. Standard Mode can actually run faster than Enh Mode because it does not use Virtual Memory and tactically there may be instances were Wins runs best in this mode., even though the user is limited to the physical Mem. of the m/c. Wins will use any Extended Memory.found by using the CPU's Protected Mode.Standard Mode is a Protected Mode system but lacks ability to create Virtual M/cs.

• Static Link Libraries (SLLs)

The main difference is that arguments can be passed to the class member functions (in the public access area) in the DLL to enable all benefits. An SLL cannot be shared across apps but is app specific and will therefore need recompiling for each app. You cannot pass arguments to the functions in an SLL.

• Subroutines.

Progs are constructed of functional modular parts. Subroutines are relatively self contained prog fragments and are known by different names in different languages. In 'C' they are called "functions" and in Pascal they are called "procedures" and they perform a particular part of the progs work acting as a building block for the prog. Key reasons for using them include subdividing and therefore simplifying the task of prog creation and error checking.

Once created logically inside a prog, subs. are removed from the main prog, reducing logical clutter and isolating the work into discrete components. Compiling or Assembling of subs. is done completely separately (see section Translation). There are two main advantages to this separation and the corresponding separate compilation of main prog and subroutine; one is that it shortens and simplifies the source code of the main prog (and also the translation time); the other is that the 'proven' sub. is available for use by any other prog. With a good overall proging strategy, it is possible for the same sub. to be used across a variety of progs, which idea forms the basis of Dynamic Link Libraries.

• Swapfile

A hidden File on your HDD set aside for use by Wins in Enhanced Mode. Wins uses this area to temporarily hold info or to 'swap' or 'buffer' info from Main Mem out to disk ( see Virtual memory) when Main Mem is running low, in order to free Main Mem. for use by other apps. The Swapfile is normally created in the Root Directory and is named 386part.par. You may either set up a Permanent Swapfile or Wins will create a Temporary Swapfile when it needs one.

386part.par is a hidden file, slightly larger than the Swapfile size you specify. This is actually the Permanent Swapfile. (see section Virtual Memory for more info.)

386Spart.par.

A 'read only' file kept in your Wins directory when a Permanent Swapfile exists. It tells Wins where and how large the Permanent Swapfile 386PART.par is.

• Synchronous

Having a constant time interval between bits, characters and events in a circuit or system. Synchronous Operation is a Mode in which each event is timed by a signal generated by a clock at a desired rate or frequency.

• System Area

The first sector on a disk, where DOS stores the control info it needs to access files on the disk. Also called the Master Boot Record, includes the Partition Table, FAT and Root Directory. This is the first directory on a drive and contains the first level of sub-directories on the disk. The root itself can only contain a limited number of files and sub-directories, the number depending on the type of disk (512 on an HDD).

• System or Start-up files

The group of files used to Boot and / or configure DOS and Wins on your PC. These include Autoexec.bat & Config.sys which have an equivalent of 'C:\windows\win.ini' and 'C:\windows\system.ini' in Wins.

Normally, System files are hidden and cannot be seen when you use the DOS 'Dir' command. They are MSDOS.sys and IO.sys (or IBMDOS.com and IBMIO.com for IBM m/c's). Another file sometimes referred to as a System file is the DOS Command processor, Command.com

A start-up file containing system specific, 'lower level' configuration info needed by Wins during start-up. The settings in this File help Wins run on a wide variety of DOS based systems.

SYSTEM . INI.

WIN . INI

A File containing info and parameters to control your Wins environment. For example, Wins.ini stores the desktop colour preferences you have chosen or the Wins app you wish to start automatically.

• System Virtual Machine.

The Virtual M/c that the Wins Kernel runs within.

• Table : definition

The arrangement of data in rows and columns or an array of data in memory, or on some other storage medium, which is so organised that individual items may be retrieved by the specifying of keys stored as part of each item. Sometimes items may be located by specifying their position in the table. The proging equivalent of a table is a collection of values of the same type referenced by their own row and column position. This table equivalent is known as an array in C++. The array acts as a definition of a collection of variables, one for each of the table entries, for use like any other variable.

• Task Switching.

The process of switching from one app to another in the Foreground. This is done by using "ALT+TAB" (Task Switching) or by using "CTRL+ESC" (Task Manager) and not to be confused withmultitasking.

• Terminate and Stay Resident Program (TSR's).

The common name for a DOS prog that loads itself into Mem. the first time it is run and remains resident in Mem., operating in the background, servicing requests on demand (say in response to a combination of keystrokes), after it appears to have terminated. The TSR will however occupy Mem. space while other progs execute in the foreground. Residency gives fast access to the Prog and lets you load it over others (early task-switching). Borlands 'Sidekick' (one of the first) & Norton's 'DOS editor' are examples. Because DOS is a Single-tasking and not a multitasking O>S, TSR's do not actually continue to execute. They are however able to detect certain events (such as a keyboard sequence) and appear to 'pop up' back to the foreground with a window for the user to work in.

• Thread (see also Multithreading and Multitasking)

In a multithreaded O>S such as Wins NT, the thread is the basic entity to which the O>S allocates a slice of CPU time. The thread has access to the same code, data, and system resources as the task (program) which started it.

• Timer Interrupts

There are two interrupts relating to the system clock chip in a PC. They are INT8 (hex) and INT1C, known collectively as the Timer Interrupts. When software requires timer related operations, it usually hooks onto INT1C (widely considered the interrupt to hook for user operations) and occasionally INT8, which is not considered as wise a choice. Some progs alter the rate at which these interrupts are generated by the system clock chip (default is 18.2 times a sec.) When they do they are expected to maintain an emulation of the default rate. If they do not the System will no longer be kept correct and other operations such as disk I/O may fail.

• Translation (Program)

There are three main ways for a proging language to be converted to m/c language instructions or 'ones' and 'zeros'; Interpreting, Assembling and Compiling. The translators are named the Interpreter, Assembler and Compiler respectively.

Interpreting means the prog essentially is translated into m/c language 'on the fly', that is, as it is being carried out. The interpreter carries out the steps of the prog and 'step by step' performs the work , executing the instructions 'on the fly'. Translation is being done at the same time the work is carried out, two sequential tasks for each line of code. This method is inherently slow and inefficient, but flexible. Much of the power of progs comes from repeated steps (i.e a loop) and so plenty of instructions are repeatedly translated when a prog is Interpreted. However changes, adjustments or revisions can be made on the spot and accommodated immediately. The 'Basic' that comes with DOS is interpreted as is the more advanced Visual basic. In a strict sense, from the PC's and the O>S point of view, the prog being executed is the Interpreter and what you think of as the prog is just the data the interpreter is working with.

Assembly and Compiling aren't done that way but are translated in advance and permanently converted into m/c language by the prog developer before the prog is used and so the translation is part of a development process. Progs available in this way are complete in themselves in contrast with interpreted progs which can only be used if you have the Interpreter as well. The compiler is given the very creative and demanding task of deciding what kind of m/c lang. instructions will be used and makes strategic decisions on how the computers resources are used i.e what the registers will be used for. There is an enormous potential for difference in the quality of compilers and while one may generate efficient code another may not be so efficient. These differences do not apply to assemblers which perform a very mechanical and uncreative conversion of the progers instructions into m/c instructions. (see also High-level languages and Low-level Languages).

• Uniform Resource Locator (URL.)

A standard way of encapsulating 'service type', 'socket info' and 'service details', the URL has become widespread along the World Wide Web. URL's can describe the location, access method and contents of any resource anywhere on the Internet. A 'logical address' that identifies a resource on the Internet.

A breakdown of a URL is instructive, the first portion gives the protocol to be used when the 'browser' tries to access the subsequent address. For example the URL:

" http : // www . znet . com / ~pcmag / utils /example . htm "

is the Internet address of a Web page giving access to 'PC' magazine. 'HTTP' is the name of the protocol (in this case HyperText Transport Protocol or 'service type' used to access the 'page' or referred to also as a 'resource type') and in the example above the doc should be accessed via the specified protocol, telling any client software how to make the 'call' to the server. The servers location is in the portion immediately following ' // ', which signifies the start of Internet info and is followed by the 'address' or 'site name', 'Web' sites normally starting with 'WWW' which can optionally be followed by a user name and password. 'ZNET' is the institution that operates the server; '.com' signifies a company as opposed to '.gov' for government, '.org' for non-profit organisation, or '.edu' for educational institution. Following the next ' / ' is a typical directory structure showing a location in the filing system of that server of the file itself so PCMAG/UTILS is the directory on the host PC; and 'EXAMPLE.HTM' is the HTML filemname for the page itself.

There are many options for each of these fields, ftp: the original Internet file transfer protocol, gopher: for a gopher server, archie:, mailto: to specify an Email address, and news: for Usenet groups are common 'resource types' while port numbers can be appended to the address. URL's can also refer to local files on a LAN or HDD.

Hypertext Markup Language (HTML) is an ASCII text-based, script-like language for creating hypertext docs like those on the Internet's WWWeb. As URLs are plain ASCII text, they can be included in docs and retrieved by progs. The best example of this is the Web , for which the URLs were originally designed. Here, URLs are commonly included as part of longer strings, called tags, (that are combined with text to form the HTMLanguage, see section) are embedded in docs and link text within them to resources elsewhere on the Net.

Browsers

Programs (browsers) designed to retrieve and display Web pages can follow those tags, automatically switching protocols to cope with whatever type is specified so browsers can move around the Net, seamlessly. The first portion of the URL gives the protocol to be used when the browser tries to access the subsequent address. This is one of the keys to the flexibility of the Web and this field can contain anything that the browser understands. HTTP was developed originally to support the Web and like nearly all Net protocols, HTTP is client / server , the web browser (client) 'talks' to the server and negotiates which formats the two ends of the conversation both understand. HTTP is not complex, having few options, and so leaves most of the work to the other parts of the system. HTML pages can contain embedded graphics, tables and other data and most graphics are in either GIF or JPEG format, although not all browsers can cope with the latter. Where data is found that a browser doesn't know how to deal with, it can call up an external prog to help.

Java

Java is an object orientated language, an adaptation of the C++ from Sun Microsystems, one of the big players in RISC architecture systems, and is a Web site development language, adding dynamic, interactive content to Web pages. Progs are compiled into an object code that can then be downloaded across the Net onto a m/c and executed. These could be short little progs to provide say a quick animation or something much more substantial. The key is that Java progs should be able to run on any m/c loaded with a Java Interpreter (no recompiling), usually a component to a Web browser, any m/c means Intel or PowerMac, so giving platform independence.

Theoretically, this could be a way of overcoming the market stronghold of Intel and MS and mean advanced Internet apps for all, but there is a drawback. Underlying the system is the concept of the virtual processor, which means that a set of instructions to be executed has been defined, rather like the instruction set of a modern CPU, and these instructions are the target when a Java app is compiled. When the prog is run these instructions are again translated into the m/c code of the target CPU. Another name is CPU 'emulation' such as running x86 software on a PowerMac. There is no native silicon CPU on which Java progs will run and running in emulation mode will mean a slower execution time than executing native code.

Sun has also developed a browser, HotJava, that allows software to download progs as needed from Web servers and this has been demonstrated with voice output, 3D viewers and spreadsheets. Java Workshop is the latest Multi-platform, Java based, Web development environment from SunSoft (the software division of Sun Micro systems) offering many attractive features for developers interested in creating Internet enabled apps. If the 'network' (streamlined, no extras, for the Net) PC is to catch on it needs to run a smaller, less clumsy O>S than what currently exists. Enter 'Java the Operating System', written in Java, however Sun has a problem. As long as Java is regarded as a PC or Mac 'ad on' then the enormous consumer market is largely barred to the company. JavaO>S is an attempt to bridge the gap and produce a minimal O>S that will run Java and nothing else ideally on one of Sun's new Java specific chips.

• Universal Asynchronous Receiver Transmitter (UART.)

A chip in your computers circuitry which controls the Serial Communications ports (e.g. COM1). IBM chose the '8250' for the serial ports in the original PC. Enhanced versions of the same chip or custom logic that mimics the '8250' are still in use today.

• Upper Memory Area & Upper Memory Block (UMB.)

The 384k of Mem. immediately above the 640k Conventional, usually reserved for System hardware such as a display adapter.

A UMB is a portion of the Upper Memory Area that remains unused. Wins on an x386> (Enh. Mode), can use memory management software to copy info that is normally held in Conventional mem. into the Upper Mem. The more 'Add-in' Cards , the less Upper Memory available. A Memory Manager such as MemMaker can free up Conventional Memory for Wins by creating UMB's in free Upper Memory and loading Memory Resident Programs and Device Drivers there, freeing up Conventional mem. for apps. Part of Wins 3.x has to load in either Convent. or Upper Mem. to support the File System and other DOS related Functions. The more Upper Mem. that Wins has to use, the more Conventional mem will be free to run DOS apps. DOS 6.22 can also load part of itself into the High Memory Area to free still more.

• Virtual 8086 Mode (V86 Mode.)

DOS apps formed the basis for using the PC for a long time and most of these apps were written at a time when the standard PC ran one app. only. This had total control of the entire m/c. An O>S such as Wins'95 has to deal with a DOS app in a different way to the Wins specific apps running on it and each DOS app runs on what Intel terms as a virtual m/c (VM) space (see section).

A virtual DOS m/c runs in the V86 mode of the CPU, all the other VM's in Wins run in protected mode. V86 mode creates multiple 1MB 8086 m/c's in protected mem, each m/c having its own copy of DOS, device drivers, I/O space, and everything else that a normal 8086 would have, except for the hardware.

Starting with the x386, a m/c could be set up to 'simulate' multiple 8086 Real ModeCPUs. This VM mode allowed each user or task to operate as though it had an entire Real Mode 8086 system all to its self. An emulation of Real Mode in a Protected ModeSystem.

• Virtual Devices.

The abstract layer 'separating' App. software from hardware. For example, the Display Driver implements a Virtual Display Device. Wins apps place 'calls' into the GDI (Graphics Display Interface) module that calls the Driver which actually writes to the screen. Since all Drivers provide (essentially) the same services, the apps (usually, to some extent) do not have to be aware of which hardware actually underlies the virtual device.

• Virtual Device Driver (VxD, Virtual 'anything' Driver).

Available only in Enhanced mode, VxDs make Wins a much 'safer' environment to work in and they work faster. A Device Driver for Wins or DOS on a x386, the code being stored in a Virtual Device File. The original function of VxDs was to extend Wins on an x386 so that it could support multiple Virtual M/cs. Thus VxD's imitate hardware so that multiple VirtualM/cs could run and 'think' they were the only Virtual M/c running.

The VxD is now taking on a more traditional Device Driver role as Wins progresses to newer versions. VxD's allow for Device independence by providing a common set of functions for each Hardware Device.

Wins'95 provides this alternative type of Device Driver which enables Wins to talk with the devices on your system without switching to real mode. Your system remains more stable, runs faster and recovers from errors better than when using real mode drivers.

• Virtual Machines (VMs)

An Executable Task consisting of an app, supporting software, memory and CPU registers, the only thing missing being the hardware itself. Hence the name VM, intangible but does exist. As far as the app is concerned there is no difference between a VM and any 'real' m/c that it could run on. Essentially the CPU fools the app into thinking that it's the only app running on your m/c at that moment. Each VM has its own memory space and access to devices on the system. You can have many VMs running on your one physical m/c at the same time. VMs are created by the Virtual Machine Manager for each non Wins app. and one for Wins itself, the System Virtual M/c. (see Virtual M/c (System)) Apps running in a VM use the a CPU mode called Virtual 8086 Mode (see section) where the apps get copies of all Real Mode related data. This includes address space, the Interrupt Vector Table and mappings to ROM BIOS, DOS, TSR's and Device Drivers. VMs can be thought of as a way of separating tasks so that they can't interfere with each other.

A system that uses multiple copies of another computers hardware and software to create a m/c environment that can be used to test software & hardware designs. The VM allows a large memory capacity through the use ofVirtual Memory, and provides simplified software and improved development reliability. The technique maps the memory plus the instructions; when instructions are executed, the m/c traps and implements them directly.

• Virtual Machine Manager (VMM.)

Supports multiple Virtual M/cs in Wins and is the basis of Wins Enhanced Mode. Ever wonder where the exact centre of Wins'95 is ? This is it, the component that holds everything else together. The VMM takes care of task scheduling and starts and stops every app on the system (including any DOS apps). The O>S component that manages virtual memory on your m/c as well. The app uses the Wins API (middle man) to make the request rather than 'talk' with this part of the system directly. Since the VMM handles all memory allocations, it also acts as a DPMI (see section) server for DOS apps that run in protected mode. The VMM is responsible for inter-task communication and all Dynamic Data Exchange (DDE) and Object Linking and Embedding (OLE)requests filter through this section of the O>S.

• Virtual Memory

Virtual Memory is a service provided by a Protected Mode O>S which works in conjunction with a built-in feature of the CPU to use external storage ( the HDD ) to simulate large amounts of Real Memory (RAM). This makes more Memory available for other apps. An x286 > Pentium can use it in addition to Real Memory and an x286 can address 16MB Real, 1GB Virtual, x286> can access 4GB real, 64TB Virtual.

A Memory technique that transfers info one page at a time between Primary and Secondary Memory and adds only the page swapping time to the operating time. This permits a prog to be larger than Main Memory, and with the use of a pointer arrangement, software demands are less than other types of Segmentation Systems. Virtual Memory Systems allow Progs as if Memory capacity were unlimited (considering 64TB) and leaves room for more progs. The O>S keeps the Pages of Prog on disk and out of use until required. The physical space on your HDD is used as actual Memory by Wins. Your HDDs physical space is reserved in a hidden file called a Swapfile. Wins for Workgroups has Virtual Memory Settings, described below:

Swapfile Type :- Options are Temporary, Permanent or None. Using a Permanent Swapfile improves the speed of Wins because the Swapfile is contiguous and accessing it generally takes less time than accessing a non-contiguous Temporary Swapfile (since the HDD does not have to jump around to find info). Because a Permanent one is contiguous, you can create a Permanent Swapfile only as large as the largest contiguous free block of space on your HDD. If you choose to create a Temp. Swapfile on a Network Drive, Maximum Size does not appear and Rec. Size changes to Rec. Max. Size. n.b you cannot create a Permanent Swapfile on a Network Drive.

Swapfile, Recommended size :- This value shows the recommended size you should specify for a Permanent Swapfile to achieve best performance. If you select Temporary as the Swapfile type, this info changes to Rec. Maximum Size, displaying the Rec. Max. Size that the Temp. Swapfile should grow to. This value reflects the most efficient use of your disk, based on the amount of available space. You can select None as the Swapfile type.

Swapfile, Max. Size :- Shows max. size for a Permanent Swapfile, determined by the amount of contiguous disk space found on the selected drive. If you select Temp. or None as the type, this info does not appear in the dialogue box.

Swapfile, New Size :- Use to specify the size of your Swapfile. If you are creating a Permanent Swapfile, this is the amount of space on the selected disk that will be allocated to the file. If you are creating a Temp. Swapfile, the Swapfile cannot grow to exceed this value.

Cache :- A larger number may improve performance but will reduce the amount of Mem. available to other apps and to the System.

• Visual Basic 'VB' ( & professional)

Has become a very popular Wins development tool. More than a language, a complete proging environment, the underlying language is a new version of MS Basic that enables professional looking Wins progs without the developer having to deal with esoteric commands. Progers can now use standard Application Proging Interface (API) calls and place graphical elements such as buttons, Windows menus and dialogue boxes on the screen easily. VB is able to provide this functionality through a run-time interpreter (non compiled) that translates straightforward VB commands into an assembly language version of the unfriendly Wins API calls. (see Translation and high / low level languages)

Professionals get an advantage in speed when producing prototypes and examining alternatives, before dedicating more hours of proging them in a language like 'C'. MIS depts. use it for building front ends and Client / Server apps. VB can also be used to create finished products which are free-standing, run-time progs. However these must be distributed with the VB run-time interpreter library file, vbrun300.DLL (installed in windows\system), through which VB prog instructions are translated into executable commands as the prog runs. VB can be thought of as something of a hybrid of interpreted and compiled languages and is unsuitable for many high speed proging tasks but professional developers still rely on other languages (compiled or assembled) to produce most of their final products.

Key to the popularity of VB are its extensions, in the form of VBX's. These are Dynamic Link Libraries (DLL's) with special 'wrappers' and are often referred to as VB Custom Controls. A simple VBX typically provides a single graphical object, such as an animated button or toolbar. A more advanced one could be a word processor, spell-checker, charting module, CD player, spreadsheet or DB query tool, requiring you to simply hook it into your VB code. There are many VBX's available, and usually have free run-time licenses.

VB is certainly an amicable solution for many Wins proging problems. It's inexpensive to purchase and makes use of Object Orientated Proging practices. Many 'C' progers reject VB, but not all are so short-sighted, utilising their 'C' skills to build the functionality of their progs into DLL's and then using VB to develop the user interface and screen components.

Custom Control

A .DLL file having the extension '.vbx' which, when loaded into Visual Basic, extends the 'toolbox' by adding extra controls.

• Workgroup

A collection of computers that belong to a common group. Each Workgroup is identified by a unique name. Computers in the same or different Workgroups can share printers, directories and ClipBook pages. In the 'connect' dialogue boxes, computers are listed by Workgroup name.

• Windows Application Programming Interface (API)

(See also section Application Proging Interface). One milestone in computing history will be the movement of Wins apps and the user base from a 16 to a 32-bit environment. But converting any large app from 16 to 32-bit is no easy task, the problem being compounded by an environment originally written for 16-bit m/c's with (apparently) little thought for the future. MS has provided three solutions and three different but strongly related API's which are described as follows.

The API associated with Windows Ver 3.x is Win16 and supplies all the 16-bit services for 'old' Wins, the API associated with Windows NT is Win32. Remember that Wins NT is best, a powerful robust O>S built from the ground up to use 32-bit CPUs and to be portable across platforms i.e to RISC m/c's and includes many enhancements to the Wins API. For the most part, Win32 is a superset of Win16. MS make the transition from Win16 to Win32 as 'painless' as possible for developers and users alike. Some functions and naturally some messages have changed, however, a Win32 prog 'looks ' very much like a Win16 prog.

To help developers who need 32-bit processing within their apps, but whose progs must run under Wins 3.1, MS introduced Win32s (the 's' stands for subset) which are a 32-bit version of Win16 but with almost non of the enhancements featured in Win32 proper. Win32s is supported mostly by a Dynamic Link Library that converts 32-bit API calls from an app to 16-bit API calls supported by Wins 3.1.

The third solution is Wins'95 which fits somewhere between the Win32s solution and Wins NT. The API is called Win32c ('c' for compatible), and it is almost as extensive as Win32 in functionality, and is more robust than the Win16 API. Wins'95 also supports Win16 to support all those 'legacy' apps that the typical Wins user will still have when he migrates to Wins'95.

The biggest benefit for progers is the flat memory address space doing away with Intel's segmented address scheme. A 32-bit app does not need to worry about segmentation any more, every call is a near call and every call is in a single segment.

No matter which API you use, there are three basic components that your app will address. The 16-bit versions of these files are 'GDI.exe', 'USER.exe', and 'KRNL386.exe'. The 32-bit versions are 'GDI32.dll', 'USER32.dll', and 'KERNEL32.dll'. The Kernel is the part of Wins'95 that provides support for the lower level functions that an app needs to run, e.g every time an app needs memory it runs the Wins Kernel to get it. This component does not deal with either the interface or devices; it only interacts with Wins itself. Every time an app writes to the screen it is using a Graphical Device Interface service. This component takes care of fonts, printer services, the display, colour management, and every other aspect of Wins that the user can see as they use their app. Wins is all about actual windows and needs a work manager to keep track of all the windows that apps create to display their various info. This is where 'User' comes in. Every time an app displays an icon or a push-button it is using some type of 'User' component function' which helped organise and keep things straight.

Special Note

Wins'95 has to start out as a 16-bit app to implement 'Plug and Play', because the Plug and Play BIOS contains separate sections for real mode and 16-bit protected modecalls. If Wins'95 started out in 32-bit mode, it couldn't call the Plug and Play BIOS to set up all your devices without a lot of overhead (because of thunking). All device configuration has to occur before Wins starts the GUI.

However 16-bit mode operations end very soon after you start Wins'95 and as soon as the 16-bit kernel sees the call for the shell, it loads an app called VWIN32.386. This small prog loads the three 32-bit DLLs that form the WIN32 API. Once this is done VWIN32.386 returns control to the 16-bit kernel which in turn calls the 32-bit kernel and finally runs in 32-bit mode from this point on. (You may notice this by observing the screen during the boot sequence.)

Procedures in the Wins API provide powerful capabilities for working with objects and data within the Wins environment. Wins includes API procedures for a wide array of tasks, from allocating memory to displaying images. Descriptions of these procedures are widely available in reference material. Wins API procedures are defined in several libraries, not all of which have the extension .DLL as part of their file name. When declaring a Wins API procedure, you therefore use the library file's name without the extension. The major libraries for MS Wins, as identified in API procedure declarations include as mentioned earlier:

USER

GDI.

MMSYSTEM.

KERNEL.

Most declarations of a Wins API procedure will identify one of these libraries for the LIB section of the declaration. To declare a .DLL procedure use the following syntax :

DECLARE type name LIB " path: library name " (arguments) AS return_type.

where the type of procedure is either a 'sub' or 'function' (nb if function, it has a return value which must be declared), the name of the procedure as it appears in the library, the filename or library name of the .DLL, the arguments passed to the .DLL of a declared data type and whether the argument is passed by value or by reference (only variables and properties can be passed by reference, otherwise use the 'by value' keyword), and the datatype of the return value (for functions).

The following declaration identifies a Wins API procedure used to play sound:

Declare Function sndPlaySound Lib "mmsystem.dll" (ByVal x$, ByVal y%) As Integer

To call a .DLL procedure, use the following syntax :

procedure_name (arguments).

As a developer, you do not need to know how the procedure is implemented to call it. In development terminology, the declaration of the procedure provides an interface to the procedure by providing the means to call the procedure, pass arguments to it, and capture a return value from it. You can make effective use of a .DLL procedure without knowing the means through which the procedure interprets the arguments, performs processing, and returns a value.

• Windows Modes

Real Mode went out with the 8088 and Wins 3.0, Wins 3.1 can run in two modes, 386 Enhanced Mode or Standard Mode (the default mode is Enhanced, Standard mode can be accessed by using the /s switch at the command line.) The newer versions of Wins only support 386 Enh. Mode. When you type 'WIN', Wins will automatically start in the most appropriate mode for your system. You can find out which mode is running by choosing the 'about' command from the 'Help' menu in Program Manager.

You can use an optional 'override' switch to specify which Mode is required, remembering you cannot run an MS DOS (non-Wins) app in a Window, if Wins is running in Standard Mode. You may wish to run Wins in Standard Mode (if not using DOS, it speeds up performance) even with more Memory available. However you may be able to run more Wins based apps at one time in Enh. Mode.

Options in Enh. Mode enable the user to specify how Wins for Workgroups controls simultaneous requests from apps for devices, such as printers and modems (Multitasking). The user can determine how Wins for Workgroups should allocate time slices (the amount of CPU time allocated to an app, usually measured in milliseconds) and PC resources when both Wins based apps and MS DOS based apps are running at the same time.

You can also specify whether or not you want to use 32-bit disk access or 32-bit file access for your HDD. You must have a compatible disk drive controller to use 32-bit disk access, it gives faster performance in transferring info to and from your HDD. 32-bit file access gives faster performance when reading and writing files to and from your HDD. It also increases the speed at which info is read from and written to your disk cache. Page-swapping or Multitasking features available starting with the x386.

• Windows (Evolution of )

Windows. Ver 1.0 :- At first, competing with entrenched Graphical User Interface (GUI) environment, the Macintosh, which was better. Not many apps made used the interface. Little more than a task-switching environment.

Windows Ver. 2.x :- Appeared in 1987, did not offer the GUI people see today with the familiar icons, not much more than a menuing system. This was due in part to memory restrictions and lack of power from the 8086, it did enabled task-switching as long as the tasks would fit in memory. Like its predecessor, did poorly in the marketplace. 286 version, 386 version offered Co-operative multitasking.

Windows Ver. 3.0 :- Emerged May 22 1990. This version began to offer users a real reason for switching from DOS based apps. Enhanced Memory support so that apps could do more and an attractive interface with extensive use made of Icons. Large software app. base emerging, but last version you could use an 8088. However running in real mode (a necessary backward compatibility for some drivers) made the system unreliable but the biggest complaint about this version was its own inherent instability. Infamous for the UAE or Unrecoverable Application Error were the system 'froze' and gave no info as to why.

Windows Ver. 3.1 :- The UAE disappeared in this version because a 'validation for system requests' was added which actually forced many vendors to rewrite software. Unfortunately some apps still violated system integrity resulting in the new General Protection Fault . (GPF) Users see less GPFs than they did UAEs and at least the GPF showed that Wins recognised that there was a problem before the 'freeze-up'. This meant that Wins could now provide more info to a vendor in an effort to find and fix the source of a persistent GPF and Dr. Watson was an included utility. Many enhancements fuelled the growth of Wins based apps 386 Enhanced Mode (Protected Mode) used Virtual Memory, Enhanced Driver Support (16 bit Drivers need Protected Mode, hence no more booting Wins on an 8088). In addition, the extra Memory allowed improved driver performance and overall reliability of Wins. Running everything in Protected Mode enables you to utilise all that Memory sitting above the 1MB Memory boundary and makes Wins 3.1 more stable than before. Still has to call on DOS for some Tasks......... more from Norton book

Windows for Workgroups Ver 3.11 :- An interim release of Wins which took care of some reliability and speed problems. Same feature set as previous Wins but bugs fixed, reliability and speed problems solved. Provided inexpensive connections for a small group of people ( a Workgroup) who need to share a few devices and some files by installing a network card and some cable, the intimate LAN connections for Workgroup computing. Also provides some simple network-related utilities like a meeting scheduler and an E-Mail system. A peer-to-peer network that uses W for W may not provide the robust environment needed for some of the tasks of enterprise computing, i.e a DB server, but will work for a small company or organisation. Many people installed W for W even on stand alone m/c's. because of reliability over previous version.

Windows NT. (New Technology) Ver 4.0 (Workstation or Server) :- Built from the ground up as a specific 32-bit O>S and a much expanded version of 'normal' Wins, being a server based and having security features and built-in Networking capabilities. For use on computers that can support 32-bit operations (also RISC platforms), DOS is therefore totally removed.

Wins NT demands a commitment from users as hardware demands are greater and who need to upgrade their apps but the rewards are there as NT is a rock solid O>S compared to previous Wins and is likely to become a dominant feature of Personal Computing in the longer term. This paves the way for Wins'95.

Wins NT has 32-bit app support, the apps using 32-bit registers and all 32 bits of an x386> and so does not have to rely on Segmentation (n.b 'flat' addresses up to 4,294,967,296 bytes ).

Ver 4.0 is a significant upgrade to Ver 3.51 and has been optimised for fast Pentiumand Pentium Pro systems and will be the basis for MS's future O>S plans. As well as the Wins'95 look and feel integration with other O>Ss and network architectures is easier, it's also possible to administer NT servers from Wins'95 Workstations. Ver 4.0 was initially intended mainly to bring the NT use interface in line with Wins'95.

The result is the 'Flat Memory Model', which is more efficient and easier for the proger. Not based on DOS and runs completely in Protected Mode, also not restricted to 80x86 Intel family of CPUs. NT provides reliable networking and so is of appeal to Corporations, but it comes with a price tag. Requires 8MB RAM min., more disk capacity and a fast CPU. Many users complain (or did at the time) that the high hardware price tag and stringent hardware requirements is not worth the additional security provided.

Windows 95 (1995) :- Code named 'Chicago', and expected to be called Wins 4.0, this latest version of Wins does not rely on DOS for Wins app needs; all the Wins Dynamic Link Libraries and supporting code run in Protected Mode. (Wins'95 does rely on DOS to run any DOS apps, to provide some low level BIOS support on non Plug and Play m/cs, and to support antiquated devices that us Real Mode Drivers).

Originally '95 was going to run on top of DOS 7.0, but the architecture was revised to replace DOS entirely. So Wins 95 is closer to Wins NT than any previous version and definitely a more rational approach. It also gives much of what we would expect from a modern O>S including Pre-emptive multitasking and long filenames.

Wins'95 uses a subset of the Wins NT 32-bit Application Proging Interface (API ) and runs completely (except for Real Mode Drivers) in Protected Mode. Supports 16-bit Segmented Memory Model to support old apps if required and of course new apps that use the 32-bit Flat Memory Model. Not only does Wins 95 perform better, faster and more reliably, but it sports a new interface as well. Wins 95 represents a half way point between Wins for Workgroups and Wins NT and also represents the future of Wins, being the first version to include the much needed Plug and Play as an integral part of the O>S. Wins '95 is no 'hack' but a true evolutionary advance over Ver. 3.1 and one that approaches the sophistication of NT.

NOTE: 8086/DOS architecture enables progs to directly access 1MB (2 power 20) worth of addresses. Moreover the top 384kb is reserved leaving 640kb to be used by progs. Memory addresses from 640kb to 1024kb have been reserved and thousands of DOS apps are written to expect this, which is a fundamental flaw within DOS in terms of future development. Even when running Wins 3.x you can have problems because certain elements are DOS based and certain types of Driver require specific Memory locations. Wins '95 has done away with all this and makes better use of resources.

A Wins proger who wants to move an app to 32-bit can so do with Win32s, and they'll run under Wins 3.1, but they will not run on 286 systems. With Win32s you are getting only part of 32-bit performance. yes the app. can use 32-bit code, but once you call a Wins API function you're back in 16-bit land. Clearly only an interim solution for heavy math's-based apps that need 32-bit code.

As usual, corporate PC co-ordinators will raise the most objections to a new version of Wins. They'll have to oversee conversions of existing systems and maintain user support during the interim period of two different (although related) user environments.

• World Wide Web (WWW or W3.)

The WWWeb is many things, including the biggest public access DB ever created, the most powerful example of what truly 'open systems' can do and the catalyst for the most rapid change in PC usage since the introduction of Wins. A global source of info connecting people and organisations together through multimedia, hypertext and the Internet. The most sophisticated on-line service in the world, but also the simplest to use. This combination, together with the ease of adding one's own info, is what has made it so important in such a short space of time. A collection of formatted hypertext 'pages' on computers around the world, logically linked together by the Internet. With a graphical web browser, such as 'Mosaic' 'Netscape Navigator' or 'Explorer', users can 'surf' the Web by clicking highlighted words on screen. Each click activates a hypertext link, connecting the user to another web location.

The Web started in its present form in 1989 as an inter-linked set of hypertext docs on a network, the first versions of the necessary hypertext tools built an interactive mechanism for physicists to share work and data. The design proved flexible enough to encompass most kinds of PC data in a most intuitive way. The WWWeb consortium now co-ordinates the Web's development. Browsers first made news in Sept '93 when 'Mosaic' was released, the first browser available outside of the academic community. Three years of intensive development have taken the Web from around 50 servers (and one experimental closed system that formed the first 'Intranet', see Internet) to the current 250 000 servers producing multimedia, real-time video, audio and links to substantial DBs. In truth browsers do not do very much, their primary function is merely to display pages of data and if a browser correctly interprets a page of HTML and shows it as the designer intended then it has done most of its job.

The Web is the fastest growing area of the Internet, a mixture of hypertext, multimedia support, and sophisticated browsing tools have made it a popular way of publishing info, keeping up to date with the hundreds of new services that appear weekly is beyond the most ardent users.

To get connected to the Web you will need a modem, a dial-up Internet Protocol (IP) stack and Web browsing software as well as an account with an IP provider. There is a wide and widening choice of browser software but the basics are the same. Each has a pre-configured home page, the first point on the Web, it will load and from there clicking on text or graphic will select a new source of info. The Web is composed of a great many data types, ranging from file directories to interactive 3D environments. The most common is the page which is a text doc composed in the Hypertext Markup Language (HTML). (see section) Links are the golden threads that bind the Web together and contain all the info necessary for the browser to locate a server elsewhere on the Web, connect to it with the appropriate protocol and select the resource on that server which will deliver the data. Links are displayed as highlighted text and the link also contains a Uniform Resource Locator (URL) (see section)

Most of the Webs problems are of its own making and the popular sites are frequently slow to respond, the rest are multiplying so fast that it's difficult to keep up to date and users can be diverted to other paths of discovery tangentially. However utilities have been developed that automate the monitoring of popular web sites to alert users when they change.

LYCOS is an automated search prog which comprises of an 'explorer' and an 'indexer' called "Pursuit", the later providing a very popular service. The explorer runs independently of the user and scouts through the Web following URL addresses for docs and as it encounters them adds the doc to its internal model of the Web. It does not keep a full copy of the doc just the title, headings, subheadings, the hundred most 'important' words, byte length and word count. The DB produced contains some unexplored URLs embedded in docs, these can be located by the indexer, letting Lycos find on request info that the explorer itself has not yet retrieved. The indexer goes through the DB, quite quickly remembering the model contains info on thousands of HTML pages. In use it works well, an "essential tool for exploring the Web".

Browser development is probably at its 'high end' and from here on other apps will start to subsume Web functionality. MS has said that most of its future desktop development will be based around Web standards, with its next O>S combining remote and local file browsing in a single desktop viewer. Its apps will be able to open and save docs across the Web as easily as if they were on a local HDD, as well as incorporate static and graphic Web data into local files. However there will still be a role for standalone browsers. Many new user will getting MS 'Explorer' whether they want it or not, as it is now the default browser for CompuServe and AOL, and will soon be present on all Wins'95 installations.