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Chapter 1 - Introduction to DRDOS

What is DRDOS?

What is a Network?

Personal NetWare

Features of DRDOS

This chapter describes DRDOS(TM) briefly for those who are unfamiliar with operating systems, and lists some of the important features of the operating system. If you are not familiar with operating systems, read this chapter and Chapter 4, ``Working with DRDOS,'' before installing the operating system.

If you are already familiar with operating systems, see ``Features of DRDOS'' on page 1-5, and then go straight to Chapter 2, ``Installing DRDOS,'' for an introduction to the installation process.

What is DRDOS?

DRDOS is a disk operating system (DOS) that coordinates the different parts of your computer to make them work as a single system. The operating system is the link between the physical parts of your computer such as the screen and the keyboard (your hardware) and the applications you run on the computer (your software).

DRDOS creates the environment in which you interact with your computer and within which your programs work.

The operating system allows you to run applications such as word processors and spreadsheets, and to organize the data you produce from your applications into files and directories so that you can manage it easily. Refer to Chapter 4, ``Working with DRDOS'' for more information on files and directories.

Your computer stores the operating system programs that manage your applications and data on disk. When the operating system is loaded, these programs are moved from the disk into memory. Memory is used for temporary storage of programs and data while they are in use. When the information is no longer being used, the information is stored on the disk again. Refer to Chapter 4, ``Working with DRDOS,'' for more details about memory and the types of disk.

The operating system uses memory to make multitasking possible on computers with a 386* processor (or later). When you enable the operating system's multitasking capability, your computer can run more than one program simultaneously.

With the correct hardware, you can use the operating system to link your computer with other computers so that you can share information and resources. When computers are linked together, this is known as a computer network. DRDOS includes Personal NetWare(TM) , which is the software you need to create your own network; see the section ``What is a Network?'' below.

What is a Network?

A network consists of several computers with network interface boards linked together by special cables. When you have a network of computers, you can share software and resources, such as printers, with other computer users.

Networking allows printers and disks (or parts of disks) which are not physically part of your computer to appear to applications as though they were. This is done by adding new disk drive letters (F:, for example) and printer ports (LPT3, for example) to those that the operating system already knows about. This way, applications can treat all disk drives and printers as though they were part of your desktop computer, even if some of them are physically part of some other computer.

Many applications default to printing on LPT1, so for convenience network software allows you to redirect output being sent to LPT1 so that it actually goes to a networked printer and not to the port on your own computer.

There are two different approaches to creating a network. The following sections explain them.

Client-Server Networking

In a client-server-based network, the server is a computer dedicated to managing the network resources. The server is the central part of the network, holding many resources in one place. Other computers (known as clients) access this central server for applications, data, and hard disk space. The server manages the sharing of application and data files among the clients using these resources. Servers also handle printing by storing print jobs until printers are available, and then directing the print jobs to their respective printer destinations.

When a computer sends a request to the server for a word-processing application and a document, for example, the server sends the application and the document across the network. The application and the document are loaded into the memory belonging to the computer. The server simply supplies the files and stores or prints documents as requested.

A Client-server Network

Peer-to-peer Networking

In a peer-to-peer network, any computer with a hard disk drive is a potential server. Any of the computers on the network offering applications, files, printers, and disk drive space to other computers is a server. A computer that makes a request for network resources is called a client. In a peer-to-peer network, resources are not located on a central computer but they are shared by the computer where the resources are resident.

The advantage of the peer-to-peer method is that you can share printers, applications, CD-ROMs, data files, and other resources without the need for them to be centrally located in one place. You also do not have to assign one of your computers solely as a server since any computer can be a server when necessary.

A Peer-to-Peer Network

Personal NetWare

Personal NetWare, the networking system that is included in DRDOS, provides the server and client software that enable you to set up a network, and to connect to Novell(R) NetWare(R) and IntranetWare servers as well.

The minimum hardware requirements for running Personal NetWare are as follows:

Refer to Chapter 18, ``Introduction to Personal NetWare,'' for an introduction to Personal NetWare.

Features of DRDOS

The following sections provide an overview of some of the important features in this operating system.

Online Manual

DRDOS is supplied with a complete online manual, DOSBook. The online manual contains detailed information about all of the features of the operating system including the basic commands, and the advanced utilities.

DRDOS also has online help available for all its commands. Refer to Chapter 4, ``Working with DRDOS,'' for more information about online help.

Memory Management

The memory management features include a set of device drivers and commands that enable you to manage memory efficiently and make as much memory as possible available to your applications. There are various device drivers available; the one you need to use depends upon the type of hardware you have. Refer to Chapter 10, ``Managing Memory,'' for an introduction to memory and memory management.

DOS Protected Mode Services

A new DOS Protected Mode Services (DPMS) interface has been added to allow specially-implemented device drivers and TSRs such as disk compressors and disk caches to operate in extended memory on computers that have 286* microprocessors and above. This makes more memory within the first megabyte available to applications and other conventionally-written drivers and TSRs. Both Stacker* (the disk compression program), and NWCACHE (the disk cache) use DPMS. More detailed information about DPMS is available to system developers in the DOS Protected Mode Services API guide which is available in HTML format on DRDOS's web site at http://www.drdos.com.

Disk Compression

The disk compression component enables you to keep more information on your hard disk by compressing the data on it. Once you have installed and run this component, it automatically uncompresses and compresses data read from or written to the disk. Refer to Chapter 12, ``Disk Compression'' for more information about disk compression.

Disk Performance

There are two components of the operating system that improve the performance of your hard disk: NWCACHE and DISKOPT.

Refer to Chapter 11, ``Improving Disk Performance,'' for more information about NWCACHE and DISKOPT.

Server Networking

The operating system network component, Personal NetWare, allows you to set up your computer as a server so that you can share your data, programs, and printers with other users on the network. You can also share application files if you have the necessary license agreements.

Client Networking

When you install the client software on your computer, not only can it act as a client of a Personal NetWare server on the network, but it can also be a client of a NetWare server. Thus, creating a Personal NetWare network does not conflict with existing NetWare server-based networks. You can also add NetWare servers to your Personal NetWare network to increase the network services available.


Security allows you to use a single username and password to log in to both your machine and the network.


Multitasking allows you to run tasks in the background simultaneously with a task in the foreground. For example, you could run a document comparison tool in the background and switch to a foreground process such as text editing. The document comparison continues to run while you edit another document.

On computers with 8088, 8086 and 80286 (or compatible) microprocessors you can still switch between tasks but a task will not continue to run when it is in the background.

File Recovery

The DELWATCH and UNDELETE commands enable your computer to keep track of deleted files, and recover them if you accidentally delete them. The backup component, Fastback Express, allows you to save files to any logical DOS device regularly and recover them later if you need them.

MS Windows 3.x Support

Many of the operating system commands are also written to run under MS Windows. You can load the MS Windows versions of these commands if you run MS Windows on your computer. These commands are placed in a MS Windows program group when you install the operating system.

Windows 95 Support

DRDOS now allows co-existence with Microsoft Windows 95 and MS-DOS 7.0. The installation program detects that Windows 95 is installed and automatically installs the DRDOS dual boot program LOADER.COM. When your computer is started, you can select which operating system to use. For more information about LOADER refer to the LOADER command or use the command line help.


If Windows 95 is detected, INSTALL creates two new files: DCONFIG.SYS and AUTODOS7.BAT. These contain your original commands from CONFIG.SYS and AUTOEXEC.BAT plus the updates from DRDOS. The original system files remain on your machine unedited.

If you select Windows 95 when you start your computer, the original CONFIG.SYS and AUTOEXEC.BAT files are executed, but if you select DRDOS, DCONFIG.SYS and AUTODOS7.BAT are run instead.

Note: In this manual, wherever, you see the file AUTOEXEC.BAT or CONFIG.SYS mentioned, if you have a machine with both DRDOS and Windows 95, replace these with AUTODOS7.BAT and DCONFIG.SYS.

Windows 3.x Utilities Not for Windows 95

If Windows is detected, any Windows 3.x utilities which can cause problems when run under Windows 95 are not installed by default.

Note: If you have Windows 95 on your computer, never use the following commands on disk volumes accessed by Windows 95: STACKER, DISKOPT, CHKDSK, DISKMAP, DELWATCH or UNDELETE. Use Windows 95 management tools only because they support long filenames.

Running DOS from ROM

Your computer may have DOS in ROM (read-only memory). In this case you will find that the operating system is already installed on your computer and starts automatically when you switch it on.

Year 2000 Support

DRDOS version 7.03 is Year 2000 compliant. The DRDOS kernel will correct the system date even if your BIOS does not.

Year 2000 support works in the following way:

Note: Although DRDOS corrects the system date, this does not prevent problems with all software applications. You must check all the software on your PC for Year 2000 compliance and load required updates to ensure that no problem occurs.

Extending Your Computer System

You may wish to extend your computer system by adding extra hard disks, memory boards, or diskette drives. You should consult your dealer about what you can use with the operating system if you are in any doubt.

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