8086 uP Require

Nah, the PC came out in '81. My dad had the first one in town, with two

160k (not 360k) 5-1/4 inch floppy drives, a monochrome monitor, no graphics, and a modified Selectric typewriter with a serial port.

Magic.

Cheers,

Phil Hobbs

Do you have also a 8087-2 ? ;-) It could be very fun to run thoses old FFT programs at full speed on my old XT :-)

We have a selection of oldish machines around here, Osbornes (2) Philips P2000C (3) IBM PS/2 Model 30 and 50, couple of each. Don't use them anymore although the Philips occasionally get run up as they have old data on them. I think most were CP/M OS except the IBM's which were early MD-DOS. The Philips have a converter/RAM card that runs MS-DOS 2.01 or thereabouts and usefully can write both CP/M and MS-DOS floppies. That has an 8088 I think.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Yes but it wasn't a knock off. They actually made some decent LSI chips that integrated much of the motherboard fumctions. The first example of such design I ever saw in fact. Wasn't the PC's glue logic made of lots of 74 series ?

Graham

I popped an 8087 into my Amstrad (PC1614DD I think?), sent that thing FLYIN! ;-)

Tim

-- Deep Fryer: a very philosophical monk. Website:

We used to deal with a surplus electronics dealer in Loughborough, UK, who had a large rack of all the special Amstrad IC's which he couldn't shift. There were thousands of them, all basically scrap. Lost the lot in a fire a few years back.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

That's not to say the group doing the PC had one

The 8088 and 8086 used the same IO chips.

I don't know how many would have gone out the door like that. 9 DIPs was

16K.

Tam

Have you ever seen an original IBM PC motherboard? It had a cassette port, the floppy controller and drive(s) were optional. There were four rows of nine sockets for the 16K * 1 RAM chips, and the firmware was in multiple 8 bit EPROMs, including their version of BASIC. The board only supported 64 K of RAM as shipped, and you only had a couple open slots to stuff with RAM boards that held up to 256K per board. If I can find it, I will scan the topside of the motherboard and post it to ABSE in a couple days.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

I ran into a retired EE from IBM who had worked on the PC project a few years before he retired. He had one of the first batch made for in house use, and they let him take it when he retired. There were slight differences from the production version, but you had to put it beside a production version to spot them. He was in tears when I returned it to him after I replaced a failed floppy controller card that had failed. A local computer store had not only refused to look at it, but the owner was screaming at him to toss it in his dumpster and buy a new computer when I ran into him in the computer store. He was shouting, No one in the world has a floppy controller card for that piece of junk! I laughed and told the old man that I had a couple dozen good spares in my collection and he was welcome to one.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

or

i

yea you are on, my memory isn't so great anymore, it was probably an '82 vintage as it had the 2 x 5 1/4 ?360K? floppies with CGA color display card and a memory expansion board. the manual mentions the ?hercules? monocrome card. the engineering firm my dad worked for purchased several as group for a discount and were using them to run some CAD application BasicCAD, CADBasic or something CAD seems i remember it was PIA to use

Never saw an actual IBM MB, but did have the original AT&T 8086 version. Sounds like the same thing, except the AT&T went modern with a floppy drive, and no tape. Did the IBM original use an MC6845 for driving the display? Occurs to me, that probably cost more than the 8088.

Tam

Yup. HGC. http://66.102.7.104/search?q=cache:M5c1jDGbUaUJ:en.wikipedia.org/wiki/Hercules_Graphics_Card+720-*-348+CGA-emulation-*+competing-technology

Yep, and the 8088. We got our first one about 1 year after they started production, and the thing that amazed me was the mobo had a half-dozen jumper-wire modifications.

I'm pretty sure the reason they used the 8088 instead of 8086 chip was to keep what later became known as the ISA bus, more simple.

--
 Thanks,
    - Win

The 8088 wasn't a cheap part when the original PC was designed. It, and the other Intel chips probably cost more than the rest of the chips on the motherboard. The 16K * 1 memory chips were quite common at the time, and I think that the non floppy version was shipped with only 32K of RAM. If I can find it, I had the BYTE magazine with the original press release for the PC, and another with their review of the first PC.

BTW, did you know that you could convert the 256K XT motherboard to the 640K version by plugging a chip into an empty socket, and soldering two adjacent pads together? Then you replaced the first two banks of RAM with 256K chips to get 640K. When I was still repairing the original XTs I did that modification to a lot of them to free up several expansion slots, and to reduce the load on the small power supplies. The non hard drive versions were shipped with a 63 watt supply.

As far as the 6845, I did see them in the early PCs and clone video boards.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

I did a 68000 design in the same time frame (while sneering at Intel). Used

64K DRAMs, but the first batch cost us about $100 each. That's why I was pretty sure they were not used in the first PC. Got the thing to legally run at 12 MHz with 0 wait states from the 128K onboard DRAM. Running C benchmarks showed performance about equal to a VAX. I may still have the same Byte magazine you allude to.

Tam

I've got an 8086-2 here, it was also out of an old Amstrad. I don't know if it still works but its possible.

If you want it, go to

and send email to that address.

-A

The first IBM PC (5150) floppy only system shipped with 16k minimum. IIRC the floppy version shipped with 48K minimum. The max on-board was 64K. IIRC 16K memory chips weren't all that cheap at the time, particularly 36 of 'em.

Yep. I upgraded hundreds of 'em. I had acess to "free" 64K chips (came off life test;). However the 256K (so called) PC-2 motherboard couldn't be upgraded easily. The XT designers added the upgrade "under the table".

I'd have to look at mine. I don't remember what it has in it.

--
  Keith

Alas, no.

I'll look out for one.

I've packed up an 8086-2 for Wayne L, that will start its journey to him tomorrow.