MS DOS Interview Questions and Answers - DoAnswers.com

MSDOS is a disk operating system for the IBM range (or compatibles) of computers. The MSDOS system resides on diskette (3.5" or 5.25") and the system files may be transferred to a hard disk unit. An operating system is a program which allows competing programs to share the resources of the computer (memory, disk, devices like printers and modems, and processing time). The operating systems first job is to initialise the hardware of the computer system, before running application programs. For personal computers, MSDOS is a single user, single tasking operating system. Single user means only one person uses the computer at a time. Single tasking means that it essentially only runs one application program at a time, and has no inherent support for running more than one application program simultaneously. An operating system provides mechanisms for running programs, handling errors, controlling devices, configuring the computer system, and for MSDOS, a user interface (sometimes called a shell).

MS DOS Interviews are getting tough these days as the technology grows faster. To get through the MS DOS interview one needs to update him/herself in a regular manner. Having said that, just before the interview, it is very important to have a quick glance of the reputed MS DOS questions and answers to make yourself comfortable during the interview process. This is where DoAnswers.com helps you in renewing yourself on MS DOS and various other technologies interview preparation.

Sure, you can. Create a primary partiton BEFORE your Windows partition (e.g. with PartitionMagic) and get a boot manager (I use the german tool 'Bootmanager', you can get a free trial version at http://www.bootmanager-pro.de). Another very good bootmanager is the eXtended Operating Systems Loader. This solution should also work with linux. I need a special program. Where can I get it? These sites have got a lot of fine DOS programs: http://www.opus.co.tt/dave

This part of the FAQ is based on my personal opinion. Some of you might have another one, please let me know about it and send your comment to cfuchs@drdos.net. Thank you. MS-DOS is the most-used DOS and most compatible :) It's very stable, but it doesn't has as many features as some of the other DOSes. It's not developed any more and it's difficult to buy it (the only chance would be something like ebay...). MS-DOS 7.x is part of Windows 9x and Windows ME contains MS-DOS 8.0. The versions > 7.10 support FAT32 and partitions > 8 GB. IBM PC DOS - Since version 5.02, PC-DOS is independent in its software package and is not longer the same as MS-DOS. Since version 7.0 or 2000 (it's nearly the same, but it's different though ;-)) ) PC-DOS doesn't have more in common than PTS/DOS or DR-DOS. PC-DOS has got a few new really great commands like dynaload. With version 6.3, IBM cleaned the source code. This speeded PC-DOS up a bit, but a few programs needed the old code and that may cause errors, but only two programs like that are known.The editor is a bit strange, I personally don't like it but some people like the /C and /A switch to edit the configuration files autoexec.bat and config.sys... You can purchase IBM PC DOS at http://www-4.ibm.com/software/os/dos/. FReeDOs - FreeDOS is still developed, it's OpenSource and it aims to be 100% MS-DOS 3.3 compatible. It comes with a big software package with lots of great tools. Visit the FreeDOS Website for more information. There you can also find some documentation stufff and lots of FAQs for FreeDOS. Unfortunately, FreeDOS isn't 100% MS-DOS compatible., e.g. Windows 3.x won't work with FreeDOS, but I'm sure that will change! A list of known bugs can be found at http://www.freedos.org/bugs/. If you want to take part in the FreeDOS community feel free to suscribe to the FreeDOS mailinglist at http://www.freedos.org/freedos/join/. Since kernel 2024h, FreeDOS also supports FAT32 partitons (kernel 2024h is an alpha-version, you can download the kernel at http://prdownloads.sourceforge.net/fdlfn/kernel_2024h_fat32.zip). There exist two different FreeDOS distrubtions: at http://www.fdos.org you can download the ripcord version which is updated more regularly - you'll find always the latest versions of the software in that package, but it might not be as stable as the "normal" distributions at http://www.freedos.org. Jeremy Davis created a bootable ISO-CD-ROM image with the ripcord distribution. It's available for download at http://www.darklogic.org/fdos/ripcord/. Please tell him what you think about it and if you have got some suggestions for further versions. Lineo DR-DOS - In my opinion, DR-DOS is the highest developed DOS. It has the best memory management, can run in DOS Protected Mode, is an 32BIT OS and comes with a taskmanager/-switcher for multitasking. If you run on a fast machine, >300Mhz, various utilities will break down because of a bug in the Borland C libraries. In DR-DOS 7.03 these have been recompiled with a fixed version of the library and they will not crash on fast machines anymore. The tool NTFSDOS (allows to read NTFS partitions) doesn't work with DR-DOS correctly, this fact shows that disk (files?) access by DR-DOS differs much from MS/PC-DOS. DR-DOS is free for personal use, but it's not developed any more. If you download the right package, it comes with Personal Netware (http://www.drdos.net/download.htm).

The possible commands of the bootmanager in the directive [BOOTMGR] in the file config.sys aren't fully described in the manual. Therefore you find here a list of the bootmanager's functions since PTS-DOS 6.42: AutoCheck = ON Checks whether a file (mostly AUTOBOOT.SYS) or an entry in the CMOS-RAM is available with a choice from the last bootmenu. If this is the case, the bootmenu won't be displayed to choose, but the system will be booted with the saved selection. That only happens if the selection had been made with one of the funtion-keys. If a selection is chosen with the number-keys, it won't be saved. During the boot, the bootmenu can be shown by pressing [ESC], although AutoCheck may be set ON. Default value: AutoCheck = OFF Color = ... Sets the color of the bootmenu. Possible colors can be found in the online help. Default: Color = LIGHTGRAY ON BLACK Example: Color = GREEN ON BLACK Default = ... Defines the paragraph in the config.pts which should be started after the "time out". This paragraph is marked with a "v" in the bootmenu. Example: Default = Standard Filename = ... Sets the filename, in which the last selection of the bootmenu is saved. Only makes sense in combination with the "STORAGE = FILE" command. Default: Filename = AUTOBOOT.SYS Example: Filename = BOOTSEL.SYS Force = ... Defines a paragraph or a number of paragraphs, which will be exectued every time, independent from the selection made in the bootmenu (simular to [PTSDOS] and [COMMON] in config.sys. Example: Force = $System Ignore = ... The opposite of FORCE, defines paragraphs, which won't be executed by the bootmanager. But that doesn't make sense in the [BootMgr] paragraph ;-) Storage = ... Establish the place where the election of the bootmenu should be saved. Two options are possible: Storage = CMOS Saves the choice in CMOS-RAM. Storage = FILE Saves the choice in a file. Defalut filename is AUTOBOOT.SYS (look FILENAME above). TimeOut = x Sets the time out value, after x seconds, a default paragraph will be started. Makes only sense in combination with the command "Default = ...". Default value: TimeOut = 5 If the space key is pressed in the bootmenu, only the directive [COMMON] or [PTSDOS] will be exectued. If there doesn't exist a shell command, COMMAND.COM will be searched in the root directory or you must enter the path and the name of the command interpreter if it can't be found.

FF: searches for matching files and changes current directory (more information with FF /?) TRUE[NAME]: displays canonized names of files despite subst or join (more information with true /?) LS: like in Unix, only in Paragon DOS > version 6.50 Some commands can be used abbreviated: ATTR[IB], BR[EAK], CO[PY], ERROR[LEVEL], EX[IT], TY[PE] and VERI[FY] The command TYPE has got an undocumentated switch /QUIET. Using this switch, the type-command won't show the message ---content of ...---

This commands aren't described in the online help or in the manual. CPUxx Beside CPU86, CPU286 and CPU386 the following CPU types are also possible: CPU88, CPU486, PC, AT, PS1 and PS2. PAUSE same syntax like ECHO (PAUSE = "", but waits for a key. SCREEN With the parameter "TTY" the screen output of the DOS is set to "Teletype-Mode" (terminal mode) TMPEXT Sets the default extension for system temp files, e.g. TMPEXT = TMP. Normal default is no extension. UMBSRV Decides, whether the built-in UMB routines (UMBSRV = INTERNAL) or extern ones (UMBSRV = EXTERNAL) are used. If you're using UMBSVR = INTERNAL, the name of the chipset must be given, the following ones are supported: 85C471, SIS471, UM82C491, UMC491, W83C491 and WINBOND491. Example: UMMBSRV = INTERNAL SIS471 USERAM Here you can define the address sector (in HEX), which should be used for the UMBs, e.g. USERAM = E000-EFFF. The UBM-functions haven't been tested yet, please tell me about your experiences. VIRTDMA Beside ON and OFF there is also the parameter HDONLY for using the virtual DMA only for harddisk access.

PTSCACHE.SYS is able to manage a RAM-disk and the disk-cache at the same time. /V Parameters for RAM disk are following: F: creates a RAM disk with KB R: Sets the number of the RAM disks's root-directory to . Default is 64 (63 files + 1 volume label) S: Sets the sector size of the RAM disk to bytes. Default is 512. Using a sector size of 256 bytes in a RAM disk smaller than 1 MB will save a bit of memory. Example (CONFIG.PTS/SYS): DEVICE = C:\PTSDOS\PTSCACHE.SYS 512 /V:512 creates a disk-cache and a RAM disk with 512 kilobytes each. The drive letters are assigned automaticly and can be influenced by the succession of the drivers loaded. Programs which had been compressed with an old PKLITE version (1.03) will crash with PTSCACHE installed.

This patch written by Jens Guenther fixes some bugs in the command.com of the german versions 6.51CD and 6.62. I don't know wheather it works with other versions, too, sorry. If you've tried it with a different version please tell me your experiences. Thank you. (51 KB)

ROM DOS is an MS-DOS compatible OS (I run MS-Windows 3.1x with it) and comes with a large software package. It's still developed by Datalight, you can get more information on their website at http://www.datalight.com/rom-dos.htm. They offer for example a webserver to control your DOS computer with a webbrowser interface or to use your DOS computer as a FTP server. You can control your DOS box with specific e-mails you send to it. It supports FAT32 and long filenames (Long File Names can be read, written, and deleted with ROM-DOS 7.1). On their website they talk about something like 'Dynamic Device Driver Loading', they explain that ROM DOS 7.1 has the ability '...to detect hardware and load device drivers dynamically and to configure itself'. Unfortunately, Datalight offers ROM DOS only to OEMs. There exist a development package for around 1200 US $, but I think that's a bit too expensive. But feel free to try the trial version on a bootdisk which can be downloaded on the Datalight website.

You can access your FAT32 partition with this driver: http://www.drdos.net/files/fat32.zip. To configure your systemfiles, add to your CONFIG.SYS: DEVICE=X:\DRFAT32.SYS /X (assuming that X:\DRFAT33.SYS is the path to the drfat33.sys file). The following line should be added to your AUTOEXEC.BAT: X:\DRFAT32.EXE /m:120 >NUL (assuming that X:\DRFAT32.EXE is the path to the DRFAT32.EXE file).

If you want to read the files on your NTFS partiton (used by Windows NT or Windows 2000), I suggest to use this driver: http://www.drdos.net/files/ntfsdos.exe. A few people told me that they had problems using this driver with DR DOS (look at Lineo DR-DOS (4.4) for more detailed information).