Microsoft open sources GWBASIC

Boris Gimbarzevsky boris at
Fri May 22 12:31:42 CDT 2020

Thanks for posting the timeline of various Basic interpreters.  I 
wasn't aware that Gates/Allen also wrote Basic for C64.  Did download 
the 8080 Basic source code out of interest, but in early 1980's had 
very little to do with IBM PC.

As was working with PDP-11's at that time, really disliked 8080 
instruction set and got a C64 instead which was considerably cheaper 
than IBM PC and much easier to write assembly code for.  C64 basic is 
fairly ugly but bought a 6502 assembler and just used Basic to 
display stuff on screen and call my work was done in assembly 
language code.  Had no trouble sampling switch data at 1 KHz using my 
"toy" computer.  A couple of guys from UBC Physiology decided to 
build a programmable stimulator based on C64 which they were trying 
to sell for $2K, considerably less than the ~$10 K that the dedicated 
device that was commonly used then.  Even though their timing 
specifications matched the expensive device, a lot of researchers 
back then didn't want a "toy" to be part of their lab setup so sales were few.

Recently found a movie Pirates of Silicon Valley which had some of 
early Microsoft history and, if depictions of individuals are true to 
reality, explains why I far preferred Mac in comparison to ugly early 
windows.  It also helped that 68000 was a very easy processor to 
migrate to after 8 years doing assembler/FORTRAN programming on a 
PDP-11.  Couldn't believe it when I had a full 512 Kb of RAM to play in.

>On Fri, May 22, 2020, 1:43 AM jim stephens via cctalk 
><cctalk at> wrote:
>>>Seems of interest.  Will be interesting to play with.
>On Fri, 22 May 2020, Justin Goldberg via cctalk wrote:
>>Interesting. I wonder if this is similar to the qbasic code in the dos 5
>>(6?) source leak that's floating around. Or if Gates wrote any of it.
>The Radio Shack Model 100 is believed to be the LAST BASIC that Bill 
>Gates actively participated in.
>"Similar"?  Well, sorta.
>A little historical perspective:
>1964 May : Kurtz and Kemeny (Dartmouth College) developed BASIC as a 
>very/over simplified system for introducing beginning students to 
>programming. "Beginner's All-purpose Symbolic Instruction Code"  As 
>simplified as they could make it with as little overhead as they 
>could, intended to be easier to GET STARTED with then FORTRAN.  It 
>is unclear whether they intended that anybody might continue using 
>BASIC once they had completed that beginner's introduction.
>1975 January : Popular Electronics ran a cover feature story about the Altair
>1975 March : Bill Gates and Paul Allen wrote a BASIC interpreter for 
>the MITS Altair 8800 using Harvard's PDP-10.  The use was 
>unauthorized, but student use had not been explicitly forbidden.  yet.
>Allen completed the bootstrap program for it on the plane on their 
>way to Albuquerque, to meet with Ed Roberts (MITS)
>1975 April : Gates and Allen formed Micro-Soft
>1979 January : Micro-Soft moved from Albuquerque to Bellevue Washington.
>(Their phone number was (206) 255-8080)
>1979 November : Microsoft dropped the hyphen
>Developed BASIC interpreters (usually in ROM) for TRS-80 ("Level ii 
>BASIC"), Commodore PET ("Commodor BASIC"), Apple ][ ("Applesoft 
>BASIC") and others.
>1981 : Contracted with IBM to write BASIC for 5150, and PC-DOS
>(PC-DOS consisted of purchasing Seattle Computer's 86-DOS/QDOS 
>("Quick and Dirty Operating System"), and enhancing it.   There is 
>extensive lore about WHY IBM contracted with Microsoft, instead of 
>with Digital Research, Inc. for the operating system.   THAT is a 
>different discussion.
>1981 June 25 : Microsoft Incorporated
>1981 August : release of IBM 5150, with BASIC in ROM, and BASIC and BASICA
>on disk that added additional features (such as DISK) to the ROM BASIC.
>Becuase the minimal 5150 came with 16K of RAM (soldered, with 
>sockets to expand to 64K), BASIC was squeezed, and BASICA was less squeezed.
>Microsoft began selling MS-DOS to OEMs.  Tim Paterson, Falcon 
>Technologies, SCP, exclusive V non-exclusive license, etc. are 
>another discussion.  Differences between PC-DOS and MS-DOS exist, 
>but are mostly few and minor (such as IBMBIO.COM/IBMDOS.COM V IO.SYS/MSDOS.SYS)
>Each OEM created their own BIOS ROMs, with occasional legal scuffles 
>when IBM thought that they were TOO similar (IBM had PUBLISHED the 
>source code for their BIOS ROM in the "PC Technical Reference 
>Manual", but did not publish the source code of the BASIC 
>ROM.)  "Clean-room" reverse engineering, "bug for bug 
>compatability", etc. are other discussions.
>Because other OEMs did not have legal access to the BASIC ROMs, they 
>could not run BASIC.COM/BASICA.COM , which relied heavily on 
>subroutines in the ROMs.
>Microsoft created GWBASIC as a substitute. Almost the same as 
>BASICA.COM, but did not require the BASIC ROMs, so that companies 
>such as Compaq could provide BASIC.  (NO! Compaq could NOT run the 
>confusion for customers having both systems, thus creating lots of 
>confusion for customers who had the renamed GWBASIC file on their disks)
>Originally, G W BASIC stood for "Gee Wiz BASIC".  But Microsoft has 
>forgotten that, and now claims to have no idea what GW stood for. 
>(Similarly the file header flag of "MZ" that differentiated .EXE 
>files from .COM stood for Mark Zbikowski)
>and THAT is what is being touted here.
>MUCH later, Quick-BASIC and QBASIC were created.

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