🚀 go-pugleaf

A heartfelt THANKYAVERYMUCH to all the kind folks who wrote me with
information, addresses and advice for turning my dumpster orphan into
a real computer!  I'm still assimilating information, and depending
on what other hardware I can scrounge I'll probably end up going one
of two routes:

   1. A hardcard with built-in BIOS upgrade

   2. An XT controller and cheapo 10MB harddisk, boot from floppy.

Or failing that, I'll just buy an XT AboveBoard card, load it up with a
gigabyte of 41256 chips and NEVER TURN IT OFF!  Yeah, right...

In article <3603@rti.UUCP> bcw@rti.UUCP (Bruce Wright) writes:
>In article <6550@cps3xx.UUCP>, usenet@cps3xx.UUCP (Usenet file owner) writes:
>> In article <19768@nuchat.UUCP> seven@nuchat.UUCP (David Paulsen) writes:
>> >
>> >I recently rescued an ancient IBM-PC from the dumpster.. and it works!
>> >
>> >My question: what exactly do I have to do to this beast to install a
>> >harddrive?
>> 
>> According to <begin underline>The Winn Rosch Hardware Bible<end
>> underline> (how do you underline anyway?) the original IBM PC introduced
>> in 1981 cannot handle advanced video adaptors (presumeably EGA) or hard
>> disks.
>
>There is a direct connection.  One problem with the old original
>PC BIOS was that there was no provision for BIOS extension ROMs.
>This mechanism is used by essentially all hard disk controllers
>(This is code that usually winds up at location C800:0).  It is
>also used by the EGA, PGA, and VGA video adapters (this is code
>that usually winds up at location C000:0).
>[...]
>Hard cards run into exactly the same problems.  The controller
>bootstrap code has to live somewhere.

This is true even of hardcards that supposedly replace the BIOS upon
installation?  Is it possible to have the original BIOS ROMS still plugged
into the motherboard, and still have "upgraded" ROMS via a slotted card,
which is how I imagine the hardcard doing its trick..?  Given my druthers,
I'd rather not mess with (a) acquiring new ROMS and then (b) messing with
the circuitboard to replace them, risking (c) frying the already ancient
and/or fragile chips that are already there.

If I can, I'd like to be able to plug in either a hardcard, or an XT
drive controller + cheap harddisk.  Possible w/o new BIOS?

Failing that, I'll probably end up swapping motherboards for one of
those $150 specials I see advertised in the Computer Shopper.. 10MHz
and 640K all on one motherboard, with no BIOS worries.

>There is an alternative.  It is possible to boot such a machine
>from floppy and then switch over to the hard drive to do all 
>the "real" work.  

Waitaminute.. THIS sounds interesting.  With my old BIOS?  I could
live with booting from a floppy, as long as my machine can at least
see the harddisk.

>You would either need a disk driver on the
>floppy, or a special program to tie the hard disk bIOS into the
>BIOS transfer vector (I don't think this is done automatically
>by the low-level MS-DOS code on such an old machine ... that's
>usually the function of the ROM-BIOS, as noted above).

I THINK I begin to understand.  The computer has the controller and
drive, but doesn't know it's there until the harddrive BIOS is
"appended" to the inboard BIOS..?  This is done upon startup?
How about drivers such as DRIVER.SYS in dos 3.3?  Could you place
that in your config.sys file (on drive A: ..heh) and tell the computer
you have an "external" device that just happens to be a hard drive?

I could live with this!  I mean, two weeks ago it didn't even
power up.. now there's hope for a harddrive.  So what if I have to
stand on my hands to get it to boot?  :-)

>If you are stuck with the old BIOS, and have _any_ cash to spare,
>you would be doing yourself a big favor to upgrade to a modern
>BIOS.  Replacement chips only cost a few bucks.
>
>						Bruce C. Wright

Do replacement BIOS chipsets come with installation instructions for
terrified non-tech folk who know (roughly) that the pointy little legs
go down, and that's about all?  I'd hate to ruin this poor, forsaken
machine.. after it survived its terrible dumpster ordeal.

David

-- 
David Paulsen    ..uunet!nuchat!seven  ||| The Curiosity Shop BBS, 713/326-3729
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Q: What do you get when you cross a dyslexic with an atheist?
A: Someone who doesn't believe in dogs.