Return to page 1 of of my starman's guide
If you really do want the answer to these questions which have puzzled programmers (coders) ever since the 8088 chip appeared, you may be interested in my theory. If you know little bout how computers work, but have looked at the Starman's pages already you may be even more confused and bewildered, but don't give up it is really more simple than you might first think, and very rewarding when you understand it.
The best place to start is not the beginning, but with the introduction of the intel 386 chip and the Microsoft DOS 5 operating system in 1991.




Computer  manufacturers were producing machines and chips but without software. The contest was on between companies like IBM and Microsoft to come up with suitable software.

If you look at the timeline in the link above you will see that on "June 11th 1991 IBM DOS 5 was released. It featured the moving of the DOS kernel and into the high memory area.
The same day, in New York, Microsoft released MS-DOS 5, followed by a party on the Hudson on board a cruise ship dubbed DOS Boat where Dave Brubeck performed 'Take Five'. The full-screen MS-MS-DOS Editor is added to succeed Edlin."

(My MS-DOS manual which I bought with my Taiwanese Eclipse 80386 machine and MS-DOS Operating System through the Bay of Plenty Polytechnic in 1990 has the Edlin Commands which create and modify ASCII files as well as Edit, the full screen MS-DOS editor which had online Help to give information about MS-DOS Editor techniques and commands. That year I also bought an external modem which came with BitCom software.)

"It adds undelete and unformat  utilities, and task swapping."

(Undelete and unformat and mirror are not owned by Microsoft.)

"GW-Basic is replaced with QBasic. It was immediately available for retail, but only as an upgrade for users of 2.11 or later."

(Our entire computer suite was equipped with machines running MS-DOS 5 in 1990 and I hadn't owned a computer -except an Epson HX-20 running basic - so mine wasn't an upgrade but a complete new package. My computer and software cost me around $12,000 New Zealand.)

"By year end (1991)  there would be about 8 million copies in use making it Microsoft's fastest ever selling software."

August 1992 Microsoft's chairman Bill Gates becomes America's richest person.

One possible explanation is the problem programmers (coders)) were having with the original 8088 series of IBM chips. If you go the Starman's web site

As you can see, Segment F000: is embedded inside this instruction, thus the reason its location is often referenced as F000:FFF0. Although the location of this far jump instruction is essentially 'set in stone' for all PC BIOS, it's not a requirement that where it jumps to next always be the same; yet every PC BIOS we've ever examined always jumps to "F000:E05B".

Of the twelve IBM engineers assigned to create the IBM Personal Computer (model 5150), David J. Bradley[7] developed the code for its BIOS. So he's the one who, among all its other details, decided where in Memory the BIOS would place and execute the code from the first sector of the IBM PC's first floppy diskette's Boot Record. The location he chose was 0x7C00 (or 0000:7C00 in Segment:Offset notation). Unlike the first 'jump address' mentioned above (to Offset 0xE05B), later BIOS authors could not have chosen a different location in Memory for loading the initial bootstrap routines without having their code become incompatible with existing boot diskettes! So IBM (and all the PC-clone companies which followed) continued to use that same location in Memory for their hard disk drive's Master Boot Records (MBRs).


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