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PC-DOS "0.90" pre-release unearthed

SomeGuy

SomeGuy

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The OS/2 museum has unearthed a May 1981 pre-release of IBM PC-DOS:

http://www.os2museum.com/wp/pc-dos-1-0-but-not-quite/

And PCjs has posted a webby emulator with an image here:
http://www.pcjs.org/disks/pcx86/dos/ibm/0.90/

PCjs is calling this "0.90" although there is nothing indicating that version in on the disk. It still calls itself IBM Personal Computer DOS 1.00, but is much earlier.

Notably, it does not prompt for a date at boot, it does not support EXE files, contains several development related tools, and includes a version of IBM Basic that does not require basic in ROM.

There is also a text file on the disk that gives even more details about development changes.

It will run on a release IBM PC.
 
Nice find, indeed.
BTW: what was the original hardware DOS was made for?
It's easily found that it was some 8086 microcomputer with S-100 bus made by Seattle Computer Products, but I'd like to see more details...
 
Very nice and funny, i tried it on my IBM XT and works fine. Funny is that default date is 00-00-81 instead 01-01-81. Also DIR command not reveal free space on floppy drive. Also not all files contains date next to file name in DIR command.
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It appears to have an advantage over later versions. I don't see EDLIN there.
 
Having a null value representing "no date" is actually completely valid in DOS/FAT. That support continued on until at least Windows 9x, although many utilities fail to recognize that.

The idea is that it is not appropriate to assign a date to a file if a user did not specify a date. Other OSes of the time often did similar. You can see that is actually the behavior of this pre-release by creating a new file without specifying a date (yes, edlin is there).

The final release 1.00 forced users to specify a date. Later versions defaulted to 1-1-80. Unless the user is a time traveler, a default of 1-1-80 is always incorrect and "no date" would have been more logical.
 
I'm impressed that .exe support was added so late to the design. It seems like that would have been a large undertaking to support with such a small window of time. It clearly shows that development+design cycles have not changed in the entire history of the PC industry! We're still cramming in features at the last minute.
 
What about included basic programs? There is strange game "spcwar" and some calculating program "kilo". I thing that the game is little bit broken...
 
KILO.BAS contains the Kilobaud magazine benchmarks which are available for many of the competing early small computers.
List the game and find the couple of movement keys in the INKEY$ routine ("K" and "M" and somehow ? "ff"). Still broken as befits early prototype code that got dropped from the final system.
 
I've tested it on IBM PC 5150 (Rev.1 BIOS) with 32KB RAM and 64KB RAM.

It boots well, but BASIC interpreter (BAS18/BAS18A is Not enough to run on 64KB RAM.
(BAS18/BAS18A works on 128KB RAM or higher.)
(Only BASICA works on 64KB RAM)
So I guess AUTOEXEC.BAT is renamed as AUTOEXEC.BAK.

AUTOEXEC.BAK content is :
date
movbas
bas18a

Also CHKDSK access disk without write protect knob.

RBAS.COM seems to be IBM PC ROM BASIC C1.00.
It doesn't work on IBM PC/PS2 with ROM BASIC.
(It should work on PC without ROM BASIC.)

This is minimum RAM to run IBM PC BASIC (Disk) / BASIC (Advanced) (0.90 beta / 1.00 / 1.10)

*IBM PC DOS 0.90 (Beta)

BASIC (Disk) : 128KB (BAS18.COM)
BASIC (Advanced) : 128KB (BAS18A.COM)
BASIC (Advanced) : 64KB (BASICA.COM)


*IBM PC DOS 1.00

BASIC (Disk) : 32KB (BASIC.COM)
BASIC (Advanced) : 32KB (BASICA.COM)


*IBM PC DOS 1.10

BASIC (Disk) : 32KB (BASIC.COM)
BASIC (Advanced) : 48KB (BASICA.COM)




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I never did understand the logic behind EDLIN. Less capable than the much older CP/M PIP--a WYSIWYG simple text editor would not have been much larger.
 
Wasn't DRI's competitor to EDLIN the similarly less than intuitive ED? ED had more features but one needed very good spatial memory to fully utilize them.

I think EDLIN was just thrown together quickly to verify that character and file handling worked with the intent of being replaced by a decent editor as soon as time permitted. IBM instead offered the Personal Editor for $50. Personal Editor was a bit too large to be the default editor for a minimally equipped IBM PC since it could handle of a maximum of 8 kB of text on a 64kB machine with 2 disk drives.
 
The only good thing about EDLIN was that in batch files you could feed it commands to manipulate text files. The end result was a pseudo-scripting ability in DOS, without any additional software required.
 
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krebizfan said:
Wasn't DRI's competitor to EDLIN the similarly less than intuitive ED? ED had more features but one needed very good spatial memory to fully utilize them.

I think EDLIN was just thrown together quickly to verify that character and file handling worked with the intent of being replaced by a decent editor as soon as time permitted. IBM instead offered the Personal Editor for $50. Personal Editor was a bit too large to be the default editor for a minimally equipped IBM PC since it could handle of a maximum of 8 kB of text on a 64kB machine with 2 disk drives.
Click to expand...

Let's not forget that PCDOS 1.0 sold for $40. Paying $50 for a real editor seems to me to be a bit silly.

I wound up adapting one that I wrote for the 8085. Still occasionally use it (greatly enhanced) when I'm coding 16-bit x86 code. VEDIT came out pretty early and even had a version that ran on the Displaywriter. Orders of magnitude better than EDLIN.
 
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A line editor like Edlin could be useful on systems driven by terminals/teletypes. Given that DOS and Edlin originated on SCP's S-100 system the design does make sense. An IBM PC-specific full screen editor would have been nice with early DOS, but obviously IBM didn't feel it was worth the effort.

Edlin is still present in Windows 10 - 32bit. :D
 
I can recall doing some things with PIP that I could have only done with sed under Unix (or perhaps a sed-like editor). CP/M had XSUB which enabled one to use a file as console input to a program. (Yes, it was a bit clunky). I was surprised to see that the functionality that had been in CP/M for years was missing from PCODS. And IBM wanted $99 for the (buggy) assembler.
 
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