Hardware, PC-elevATor (Applied Reasoning)


Simply ingenious

When I ordered this PC card on eBay (US) (no RAM, no software, no manual) I was very sceptical if it would work. The 64 RAM chips (SIEMENS HYB 41256-15) I could buy at least on eBay (DE) for a little money.

But nevertheless the excitement was very big. After all RAM components had been checked individually and plugged in and the software had been installed, the big moment came. Now just run the setup program, enter the hardware components correctly, restart the computer and run the program UP.EXE ...

Bull's-eye, the accelerator card is working properly.

Compared to other accelerator cards the PC-elevATor is a plug & play (PnP) system. With some other cards the old processors must be completely removed. The PC-elevATor whereas can be switched ON/UP and OFF/DOWN.

PC-elevATor (Applied Reasoning)
PC-ELEVATOR (Applied Reasoning, Rev 2.0), 2 MB RAM, Intel A80286-10
PC-elevATor (Applied Reasoning)
Now with numeric coprocessor Intel D80287-8 (Update: 19.12.2019)

This card is already a newer model (Rev 2.0), because an 80286-10 is installed. The first models have an 80286-8 processor. A 12 Mhz CPU (PGA68) can also be inserted into this card. But then the jumpers W1, W2 and W3 must be adjusted!

Important! In addition to revision 2.0, there is also revision 1.1. This has another label on the PCB, namely „PC-GT 286“, not PC-ELEVATOR. According to the information I have, this card will not work properly with the software revision 3.5 (SETUP program)! See 1st link below.

It's hard to believe, but the first model with 2 MB and 8 MHz cost $2.495 in 1985! See PC-Mag 11/1985.

It gets even better. In 1986 the 10 MHz version with 2 MB cost $2.745, plus $425 for the 8 MHz 80287 coprocessor. See PC-Mag 09/1986.

About software releases and variants

That's interesting to know:

NOTE: Since Release 3.67, most releases have had two "siblings".
There are three variants of each functional release:
a) a mainstream variant,
b) a 3270-PC variant,
c) a special OEM variant.
Release 3.84 notes (OEM)
Release 3.84 incorporates the changes in 3.83, and has a fix added for an incompatibility with the OEM's BIOS.
RELEASE 3.84 NOTES, 9 June 1987

I use this very same release 3.84, the „special“ OEM variant. Now the question arises, what is the mainstream variant? The 3270 variant should be clear, the IBM PC 3270 (XT).

Switch settings, configuration

As you can see in the picture above, there is a switch on the card. It consists of two blocks: B1/SW1-2 and B2/SW3-8. B1 sets the I/O address and B2 sets the interrupt.

With the IBM PC or XT there is only one possibility concerning the IRQ and this is the IRQ2, because all others are occupied. Unless you don't use LPT1 or COM1 or COM2 or floppy disk or hard disk.


   POS 1   POS 2   I/O ADDRESS
   OFF     OFF     31C to 31F (*)
   ON      OFF     21C to 21F
   OFF     ON      11C to 11F


   POS 3 ON        INTERRUPT 2 (*)
   POS 4 ON        INTERRUPT 3
   POS 5 ON        INTERRUPT 4
   POS 6 ON        INTERRUPT 5
   POS 7 ON        INTERRUPT 6
   POS 8 ON        INTERRUPT 7
   ALL OFF         NONE


Further configuration settings are contained in the „MBF COMPANY CONFIDENTIAL FIELD INFORMATION BULLETIN“, see below. The date of this bulletin is from 10/01/87 and therefore fits very well with the software release 3.84.

My system configuration

  1. IBM PC DOS 3.30 (de)
  2. IBM PC XT 5160 (64-256), 256 KB
  3. Intel 8088 and 8087
  4. Quadram Quadboard, 384 KB
  5. IBM 5.25" diskette drive adapter
  6. Two floppy drives (YD-580)
  7. IBM fixed disk adapter (62X0786)
  8. IBM fixed disk (WD25)
  9. Hercules graphics card
  10. ...
  11. PC-elevATor 286, 2 MB

My PC-elevATor configuration

Important! As already mentioned at the beginning, I got the card and the software completely independent from each other. That's why it's a lucky coincidence my card and software fit together.

The SETUP program has the revision 3.5, but the system driver UPDEV.SYS has the release 3.84! I got confused here at first. This release is from June, 9th 1987. As far as I know, this is the only release available on the Internet.

Note: You have have to install the software from floppy drive A:. The SETUP program creates a configuration file called UP.SYS on drive C:.

The other programs on the setup disk have the copyright date „1987“, in other words this software seems to be one of the last (newer) ones, because the successor, the PC-ELEVATOR „386“ was available from 10/1987 on. The first „PC-GT 286" came on the market in 1985.

Checking the accelerator RAM

The RAM should always be diagnosed first before the card is configured! Although I had checked all my (64) RAM DIPP with my RAM Tester before, one of them probably didn't have a real contact. But the legs were plugged in correctly! Result: Sometimes there were problems, sometimes none. Basically the card worked! The acceleration function worked fine, only the memory utilities caused some problems.

The diagnosis must be made with the DIAG program. A complete run takes at least five minutes, rather ten.

RAM locations on the PC-elevATor

Banks B0 to B3:

   h g  f e  d c  b a

   V D  x x  x x  L x   8
   x x  x x  x x  x x   7
   x x  x x  x x  x x   6
   x x  x x  x x  x x   5
                            rear side PC -->
   x x  x x  x x  x x   4
   x x  x x  x x  x x   3
   x x  x x  x x  x x   2
   x x  x x  x x  x F   1
    B3   B2   B1   B0
     \  /      \  /
     2nd MB    1st MB
   x = 41256 chip
   F = first chip (in B0)
   L = last chip in B0
   D = my damn chip (B3: xxxx xxxD xxxx xxxx)
   V = the very last chip (64th)
   B0: Fxxx xxxx xxxx xxxL
   (see 1st figure above)
   Each bank is 2 x 256 = 512 KB
   Each chip (x) is 32 KB (256 KBit)

I had the luck that my „damn“ RAM chip was at g8 (in the 2nd MB). So the 1st MB (B0+B1) was fully usable and the card basically worked. If the error would have been in the 1st MB, then the card would have been completely dead.

Test configuration with all memory utilities

Memory utilities
Memory utilities
Output UP.SYS
Output UP.SYS
Checking memory usage with CONTROL
Checking memory usage with CONTROL

Do you notice anything about this picture/result? The TOTAL MEMORY is specified as 2.496 KB! How come?

In my system are installed: 256 KB (mainboard), 384 KB (expansion card), 2.048 KB (PC-elevATor). In total these are 2.688 KB. Quick calculation: 2.496 - 2.048 = 448! Oops! With other words, the accelerator card must partly use RAM on the expansion card and on the mainboard. Where else would the memory come from?

Memory usage with UP/M
Checking memory usage with UP/M

Going UP und DOWN

With the PC-elevATor card you have to call the program UP.EXE to switch to 80286 mode and DOWN.EXE to switch back to 8088 mode. When UP.EXE is called the first time, a warm boot takes place. With the second UP there is no warm boot, the switchover takes place immediately.

If the card is in 286 mode (UP) and you make a warm boot, then the accelerator card remains in UP mode! The card will not be reset.

If you change settings after the first UP and DOWN you have to reset the card with UP/R. If you do not, the card will remain within the first SETUP status. A new UP.SYS is only read again after a reset.

NOTE: You can use our "hot-key" (an unadvertised feature) to manipulate the cache and spooler without having to get to a DOS prompt. To use, you hit CTRL-ALT-RSHIFT (RSHIFT is the right hand shift key); you will get a prompt showing your options ("c" for cache, "p" for printer, etc.) If you have no spooler, the "p" option allows you to toggle the state of FASTPRINT.
RELEASE 3.84 NOTES, 9 June 1987

If you hit "v", the release/version info will be printed on the screen. I my case:

Release ID is 'Release 3.84'
Version ID is '06/09/1987 13:38 SERVER'

UP command flags

UP command flags
UP command flags (from HELP.EXE)

A litte benchmark

Note: My old (first) system configuration with 512 KByte DOS RAM and a NEC V20!

8088/87 mode

8088/87 mode
SysInfo: 8088/87 mode
8088/87 mode
Main system benchmark: 8088/87 mode

80286/287 mode

80286/287 mode
SysInfo: 80286/287 mode

Note: Although no expanded memory has been set up in the setup program, the memory manager is still started.

80286/287 mode
Main system benchmark: 80286/287 mode


-/- 8088/87 mode 80286/287 mode
Dhrystones 379 2492 (1.42 DMIPS)
Whetstones 122.9 272.7

A VAX 11/780 from 1977 has 1.757 Dhrystones or 1.0 DMIPS.

Important notes on accelerator boards

Whether the PC-elevATor also supports the protected mode I cannot say/test, because the hardware and software I use is too old to install Windows/286.

„Some of the larger boards can currently switch to protected mode using their own memory on the board, but even here it’s quite improbable that this memory will be accessible in a protected-mode DOS.“
PC-Mag 09/16/1985, p.134
„You’re looking only for improved processing speed, an accelerator board will give it to you. If you’re looking for anything else, you’re going to be disappointed.

In short, accelerator boards will not turn your PC or XT into an AT.
PC-Mag 09/16/1985, p.134
„Accelerator cards will not significantly improve disk access speed. They will improve the software overhead required for file I/O, but once the red light goes on, your disk will not work faster.
PC-Mag 09/16/1985, p.134

How do they work?

„The large-size boards generally use their own memory and may not even require removing the 8088 from its socket. We tested ... and the Applied Reasoning PC-elevATor.

These boards disable your system board 8088 through a DMA channel and take over your whole system.“
PC-Mag 09/16/1985, p.134

Key statement

"To accelerate or not to accelerate” is not really the question. The question is “How?” As for me. I’ve discovered that there’s really only one way to get an AT on my desk, and that is to buy one.
Charles Petzold contributing editor, PC-Mag 09/16/1985, p.134

The PC-elevATor was mainly designed for the speed increase from 8088/4.77 MHz to 80286/10 MHz in real mode. That works fine. No more, no less!

The complete SETUP program

You will see a lot of screen shots ...

Problems with

... other software or drivers

  1. Xircom PE3-10BT network pocket driver: The packet driver can not be installed in UP/286 mode, only in DOWN/8088 mode. Maybe an I/O problem, ...

... „my“ accelerator card

  1. Actually no problems, after I found my faulty chip.
  2. The 80286 & 80287 are getting hot in UP mode. With heat sinks, the temperature has risen to 53 °C (127 °F). Whereby the respective processor will be even a bit hotter.

Downloads and information

Despite a long search on the internet I was NOT able to find any user manual. Further information can be found only in the "MBF COMPANY CONFIDENTIAL FIELD INFORMATION BULLETIN", the "RELEASE 3.84 NOTES" and in the file HELP.EXE on the setup disk.

External links