If you're interested in a speed-up, I'm fairly sure a 486DX/2-66 should drop-in for the current 33mhz CPU, without any additional changes. Doubles your core speed and adds the math co-processor in one go.
On Mon, Jan 25, 2016 at 12:29 AM, Mark J. Blair <[email protected]> wrote: > To my surprise, I found something just barely old enough to interest me on > the e-waste pile at work: An IBM PS/2 85 from around 1993 or so. The hard > drive is long gone and it didn't include a keyboard, but it did come with a > model 8516 touch screen display and original mouse. I already had a nice > Model M to plug into it, plus some scsi2sd adapters sitting around waiting > for projects like this one. > > I'm new to the PS/2 line, but after some poking around I found images of > the reference and diagnostic disks necessary to set this machine up. I also > found the ADF file needed for the Cabletron ethernet card in it. The > machine has 12M of parity RAM, with one SIMM slot pair still open. It has a > 2.88M 3.5" floppy and a 1.2M 5.25" floppy. The 5.25" floppy is a > motor-eject style which I haven't encountered before. This model has a > 486SX 33MHz CPU, and the math coprocessor socket is empty. Aside from a > bunch of dust that I cleaned out, it's in pretty nice cosmetic shape. This > particular model was intended for duty as a server. > > I've been posting pictures of the machine on Twitter over the last few > days, starting on 1/21/2016: > > https://twitter.com/nf6x/media > > I replaced the CMOS battery (conveniently, a CR2032 coin cell, available > at the local supermarket), reconfigured the CMOS settings, set up a scsi2sd > as four emulated 512M SCSI hard drives, milled a pair of generic PC hard > drive mounting rails to length for use in a PS/2, and installed MS-DOS 6.22 > on it. OS/2 2.0 would probably be more appropriate for this machine, but I > don't have it. I see original OS/2 2.0 boxes in the shrink wrap on eBay, > but eBay and I are seeing other people at this time. > > Well, I seem to have it fully working aside from not having suitable > software installed to test out the touch screen and networking card. The > monitor sometimes makes a bit of high-pitch whine which by some miracle I > can still hear. Younger folks might find it objectionable. I wonder if it > would be effective as a child repellant? :) Thankfully, it doesn't seem to > set my dogs to howling. > > And now that it is cleaned up and working, I have no clue about what to do > with it! I just didn't want to see it go to the landfill or end up as toxic > dust in some poor guy's lungs in India, so I got permission and then carted > it home. I am not normally interested in PC-family machines, but actual IBM > ones interest me a bit. And the countless ways IBM found to make the PS/2 > line incompatible with regular PC lines give me things to bitch about, and > that in turn gives my life purpose. :) > > So, would any of y'all like to help me brainstorm about interesting > applications for this vintage heap, or maybe point me towards non-eBay > sources of software that it would like to run? > > -- > Mark J. Blair, NF6X <[email protected]> > http://www.nf6x.net/ > >
