On 12 Nov 98 at 10:11, Ashok Bhiman wrote:

> > In the early days of personal computers, the BASIC Operating System (OS)
> > was supplied as the default OS in Read Only Memory (ROM) in chips on the
> > motherboard.  When everybody started using DOS (Disk Operating System),
> > hardly anybody used BASIC, and those who wanted to could use newer,
> > improved versions, such as BASICA, GW-BASIC, QBASIC from
>
> My understanding is that BASIC, BASICA etc. are languages and NOT OSes. Am I
> right or wrong?

  Yes.

  When IBM introduced the PC in 1981, you could buy it without any
drives at all.  [IBM discontinued that configuration when they
realized that many buyers were hobbyists, who knew where they could
get compatible floppy drives for much less than IBM charged....]
  No drives meant no way to run DOS, so IBM included a second ROM
bank (in addition to the BIOS) containing a stripped-down version of
Microsoft's BASIC.  It could save stuff to (and read it from) a
cassette player, using a connector which you may find next to the
keyboard connector on many old 8088 boards.
  This was comparable to the facilities built into various other
early microcomputers -- Radio Shack's Color Computer, TI's 99/4,
Sinclair's ZX-81 and so on.
  Most people in those days would not have called it an OS; it was
only a half-step up from the "monitor" programs of the previous
generation that let you enter code in assembler mnemonics instead of
hexadecimal.  But it was as close to an OS as you could get without
drives.

  There were four important early versions of BASIC for the PC [and a
couple of less important ones that most users never saw or needed to
know about].  BASIC.COM was a trivial DOS program that
effectively handed control over to the BASIC in the ROM.  BASICA.COM
("BASIC Advanced") used about 64K of RAM to extend the ROM BASIC to
support drives and other features that the ROM version omitted.  Both
were included with PC-DOS.
  Non-IBM machines didn't have the BASIC ROM, and didn't necessarily
adhere to IBM's interface to the BIOS ROM.  They came with their own
version of MS-DOS, and it included a BASIC.EXE or BASICA.EXE which
included the ROM code (making it take up about 120K or so of RAM...)
and worked with the particular machine.
  As *clones* replaced *compatibles*, it became possible for versions
of MS-DOS to run across a variety of brands, and Microsoft began to
ship GW-BASIC.EXE, including all the features of the IBM BASICA.COM
but without requiring the IBM BASIC ROMs.

  For what it's worth, most computer professionals would say that
"BASIC" is a language, and that BASIC.COM, BASICA.COM, GW_BASIC.EXE,
etc. are *implementations* of that language.  Knowing how to use one
will give you reasonable expectations about how another will behave.

David G

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