PCs that support only one floppy drive in hardware

Allison ajp166 at bellatlantic.net
Wed Oct 12 19:44:29 CDT 2005

>Subject: Re: PCs that support only one floppy drive in hardware
>   From: Scott Stevens <chenmel at earthlink.net>
>   Date: Wed, 12 Oct 2005 18:39:30 -0500
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>On Wed, 12 Oct 2005 08:06:10 -0400
>Allison <ajp166 at bellatlantic.net> wrote:
>> On the whole I prefer my solution.  A simple 486/66 on a board that
>> doesnt have any "chip set" and ISA cards that are easy to find in
>> junkers.  Convenient, you bet.  The board board I selected uses PS2
>> keyboard and mouse.  I have two spare boards and the nicads have been
>> removed to prevent leakage.  Thse have done well for floppy futzing
>> from any 5.25 to any 3.5" (excluding the near unseen 2.88).
>I don't know that I've ever seen a 486 motherboard that didn't use a
>'chipset.'  The ASIC 
>'chipset' motherboards came in the late 286/early 386 era.  The big
>'Full AT footprint' '286 motherboards don't use a 'chipset' but rather
>lots and lots of TTL gates and standard Intel 8xxx LSI chips.

I differentiated ASIC glue from the other types of chipsets that are 
programable like the PCI bridges and resident FDC/IDE/Serial/parallel.
Ever try to get W9x to run on a PCI machine without the correct PCI bridge 
driver?  It's painful.

For example the 486slc/33 mb I have in fornt of me is one of those small 
footprint styles (6.75x8.75") with 5 ISA-16 slots and four 30pin simm slots.
There is an asic on that that really only glues the 486slc to the bus and
contains the 8237 DMA not any of the other LSI (5818 RTC/Cmos and 8242 
keyboard) functions.  For it's size the board is mostly connectors!

>Tony can probably add a few comments about the switch from 'regular
>logic' PeeCee motherboards to 'chipset' based ones, as he seems to be
>running a 'processor upgraded' IBM AT system specifically to avoid
>'black box' ASIC-base motherboards.

No doubt.  But I hope he reflects on my use of chipset adverse to ASIC.

>I definitely don't have any 'current solution' hardware here that I am
>wailing about not being able to use.  My Dell systems are
>first-generation 100MHz bus Pentium III systems, which makes them
>'rather old' in current terms.  Today somebody at work gave me an 'old'
>machine out of his car from home that he didn't want anymore.  Said 'you
>can probably salvage something out of it.'  Then he dropped the comment
>that it probably has an 800 MHz process.  Uh...

That 800mhz machine and definatly the PIII are way faster than anything 
I have.  The main PC here for most on line cruft is a P166mmx from around
1998 an asus board.

>I agree about the usefulness of keeping around some 'plain old' legacy
>systems from the '486 or early Pentium era.  I've always kept boxes like
>that around for things like the machine at the bench that programs
>EPROMS (my EPROM programmer is one of those Needham PB-10 ISA card
>programmers (it will last FOREVER since the most 'proprietary' parts on
>it are two 6821 PIAs)

One of those 486s has the BGLA logic analyser in it. Handy 16channel 


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