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The Ideal New IBM PC 5150

G

Great Hierophant

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What could you do if you had the money to buy all IBM parts at your disposal and had to build the ultimate 5150? Here is how I would do it :

5150 System Unit w/256KB RAM, 10/27/82 BIOS & BASIC. Math Co-Processor Option, 65W Power Supply
83-Key Keyboard

Slots :

1 - Diskette Drive Adapter w/2x Double Sided Diskette Drives & 4865 Personal Computer 3.5" External Diskette Drive Model 1
2 - Color/Graphics Monitor Adapter w/ 5153 Color Display
3 - 256K Memory Expansion Option
4 - 64K/256K Memory Expansion Option w/128K
5 - Extender Card

5161 PC Expansion Unit w/ 130W Power Supply

Slots :

1 - Fixed Disk Drive Adapter w/2x 10MB Fixed Disk Drives
2 - Asynchronous Communications Adapter
3 - Asynchronous Communications Adapter*
4 - Game Control Adapter
5 - Printer Adapter
6 - Monochrome Display and Printer Adapter w/ 5151 Monochrome Display & 5152 Graphics Printer
7 - Music Feature w/MIDI adapter Unit
8 - Receiver Card

IBM PC-DOS 3.2

* - You could put a substitute a second Music Feature Card here. Of all the options, I am only uncertain whether the Music Feature can be installed in an Expansion Unit. Of course, if you are driving two music cards, there may not be much CPU time left for much else. Since the Music Feature requires an IRQ between 2-7, eliminating an Async adapter solves the problem. Eliminating a printer adapter does not.

My primary concern is use. Every card, every drive, should have some kind of purpose in the machine. IBM made lots of stuff that simply had no real use for a home PC user. But two graphics displays are useful, especially using one for DOS and the other for programs and games. Two Async adapters can support a mouse and a modem/null-modem (I do not believe IBM marketed external modems). Two printers, one for the quick stuff (Graphics Printer) and one for more professional quality (like a Proprinter XL) would not have been unheard of.

As far using an Enhanced Graphics Adapter or Professional Graphics Controller (in the 5161), I feel that they are a much better fit in an AT machine. The PC is rather slow to be driving those high resolutions and color modes.

Finally, I have limited the hardware to items available from IBM before the PC's discontinuance on April 2, 1987. So the Music Feature card is okay, but the PS/2 Display Adapter or the IBM ISA Ethernet adapters of the 1990s are not.
 
That would be an awesome machine! But what software would you use to put DOS on one monitor and a game on another? Pretty much everything was single-tasking back then. It is useful for programming though - you can have your program's output on one monitor and the debugger on the other. I know Turbo C used to let you do this - probably other Borland products did too.
 
An interesting idea!

For me it's the simplicitity and lack of capacity that makes the machines interesting in the first place, so on that basis a straight 16k, but a 256k with the later BIOS obviously able to run many more programs people remember.

The only boards I'd add would be SoundBlaster if running with CGA, and potentially an XT-IDE to preserve the old floppies.

Dot-matrix and a daisy wheel were common.
 
I'd probably skip the two memory cards and put in a AST six-pack premium, that way you can go to 640k and have another 640k available as EMS -- also providing you from that one card with a parallel, serial, game.... at which point I'd pitch one of the async, the game and the dedicated parallel.

I mean, if you're talking the ultimate 5150, I'd not be putting IBM cards in it; AST for memory/IO, Hercules+ instead of MDA, Soundblaster instead of music feature (did anything other than Sierra games even SUPPORT music feature), put a MT-32 on it...

I probably wouldn't even bother with the extender if I could find one of the old 7 function I/O boards as that nets you floppy, internal clock, RAM, 2 serial and a parallel... so CGA, Herc, Blaster, Hard drive... 5 slots.

Though for laughs, I'd toss a cassette deck on it.
 
If I had a 5150 that I needed to do some real work with, I'd probably throw in the fastest largest CPU card I could. Maybe a 68K one if it had enough local memory...
 
This is the pure IBM machine, or at least as pure as IBM's products would allow.

It is simplicity itself to use an MDA and CGA monitor, DOS and other text-mode programs will use the MDA, games and graphical applications will use the CGA. No user intervention at all is required other than setting the DIP switch to Mono.

The reason why I did not include a Hercules, in addition to trying to remain pure IBM, is that its graphics mode requires 32KB of RAM and there is already a CGA card in the unit. 32KB modes tend to be slow performers in the IBM PC. Ditto for Sound Blaster, games using its digitzed sound capabilities tend not to be very speedy on an 8088@4.77MHz.

No one else supported the music feature except for Sierra for games. Most of them (SCI) will play far too slowly. But midi sequencers and such could support the board.
 
Did IBM ever make a replacement for the 68K-based lab computer whose announcement just preceded that of the 5150? What did IBM sell as a follow-on product?
 
Re SoundBlaster - AdLib was certainly slow, but I'm not sure about the SB. The infamous 8088-corruption manages 25 frames a second (text mode!) whilst playing 11kHz.
 
The IBM Music Feature is for the most part solely MIDI-based in hardware, and doesn't really need too much CPU overhead. You simply set it up, and then provide MIDI data when appropriate. It's IRQ lines are either activated by the TxRDY and RxRDY flags, and/or the programmable timers on the card. The timers can be programmed to to wait up to 2 seconds between each interrupt.
 
Ah, I see - you didn't mean using the MDA and the CGA at the same time - just using the MDA for the higher-resolution text when you don't need colour or graphics.
 
hello
you write "(I do not believe IBM marketed external modems)" - I have a 7855-10. Have not powered it up. But it is a nice "ibm" logo modem 9600 baud I think. (from 1992) :)
/cimonvg

Great Hierophant said:
What could you do if you had the money to buy all IBM parts at your disposal and had to build the ultimate 5150? Here is how I would do it :

5150 System Unit w/256KB RAM, 10/27/82 BIOS & BASIC. Math Co-Processor Option, 65W Power Supply
83-Key Keyboard

Slots :

1 - Diskette Drive Adapter w/2x Double Sided Diskette Drives & 4865 Personal Computer 3.5" External Diskette Drive Model 1
2 - Color/Graphics Monitor Adapter w/ 5153 Color Display
3 - 256K Memory Expansion Option
4 - 64K/256K Memory Expansion Option w/128K
5 - Extender Card

5161 PC Expansion Unit w/ 130W Power Supply

Slots :

1 - Fixed Disk Drive Adapter w/2x 10MB Fixed Disk Drives
2 - Asynchronous Communications Adapter
3 - Asynchronous Communications Adapter*
4 - Game Control Adapter
5 - Printer Adapter
6 - Monochrome Display and Printer Adapter w/ 5151 Monochrome Display & 5152 Graphics Printer
7 - Music Feature w/MIDI adapter Unit
8 - Receiver Card

IBM PC-DOS 3.2

* - You could put a substitute a second Music Feature Card here. Of all the options, I am only uncertain whether the Music Feature can be installed in an Expansion Unit. Of course, if you are driving two music cards, there may not be much CPU time left for much else. Since the Music Feature requires an IRQ between 2-7, eliminating an Async adapter solves the problem. Eliminating a printer adapter does not.

My primary concern is use. Every card, every drive, should have some kind of purpose in the machine. IBM made lots of stuff that simply had no real use for a home PC user. But two graphics displays are useful, especially using one for DOS and the other for programs and games. Two Async adapters can support a mouse and a modem/null-modem (I do not believe IBM marketed external modems). Two printers, one for the quick stuff (Graphics Printer) and one for more professional quality (like a Proprinter XL) would not have been unheard of.

As far using an Enhanced Graphics Adapter or Professional Graphics Controller (in the 5161), I feel that they are a much better fit in an AT machine. The PC is rather slow to be driving those high resolutions and color modes.

Finally, I have limited the hardware to items available from IBM before the PC's discontinuance on April 2, 1987. So the Music Feature card is okay, but the PS/2 Display Adapter or the IBM ISA Ethernet adapters of the 1990s are not.
Click to expand...
 
Definately need vga. I have an et4000 card in mine. It has a ramdac that supports high and true color modes. AND, it has the vesa modes in its bios - saves from loading a tsr and using memory.

I also have a tiny turbo (286/8mhz with cache), it makes things much,much faster...

I have the ast 6pak premium, bat am really thinking about replacing it as it only supports lim 3.2 (windows requires lim 4.0)

I'm limited to 5-slots; wish I had the expansion chasis...
 
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