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Questions about IBM 5150

musicforlife

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Jan 10, 2018
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I will acquire 5150 soon and I have these rolling in my mind. Sorry if some questions are too obvious.

- Is there a way to install hard drive? Second power source is the only option?
- My computer is 5150 but somehow the case is from IBM XT. Is there any reason / possibilities to hunt down original case or do I just need to replace the logo icon?
- How much memory can be upgraded via ISA memory boards? Does the memory need particular sizes for parity or does it just accept anything you put into it?
- Was the highest supported format DD floppy of 720kb? Any way to use HD floppies?

Thanks.
 
The answers to your current questions and many more you will have in the future can be found in the 5150/5160 FAQ at the top of this forum.
 
That's not a possibility. The slots are spaced differently. :)

Well anything is a possibility. A motivated person with a dremel and a drill could make a 5150 motherboard fit in an XT case :p

But I think it's more likely somebody just swapped the badge.
 
Well anything is a possibility. A motivated person with a dremel and a drill could make a 5150 motherboard fit in an XT case :p

But I think it's more likely somebody just swapped the badge.

I thinks it's even more likely they just switched the top cover since the two (5150 and 5160) have the same exact cover.
 
- Is there a way to install hard drive? Second power source is the only option?
A smaller later model hard drive or an XT-IDE with CF card will not require as much power as full heights of the period, usually allowing a single supply to work fine.

- My computer is 5150 but somehow the case is from IBM XT. Is there any reason / possibilities to hunt down original case or do I just need to replace the logo icon?
The case covers are interchangeable, identical and they got swapped around all of the time. So yes, you could just replace the badge.

- How much memory can be upgraded via ISA memory boards? Does the memory need particular sizes for parity or does it just accept anything you put into it?
Depends entirely on the ISA memory board. The better ones will upgrade all of the way to 640k and may even add paged EMS memory.

- Was the highest supported format DD floppy of 720kb? Any way to use HD floppies?
With the standard IBM floppy controller, yes. There were various third party 8-bit high density controller cards, but those are hard to find.
 
When I was in junior high, around 1991, my dad and I installed a Kalok 40 MB hard drive in our IBM 5150. :) Back then, it was much easier to find an 8 bit ISA IDE card. Fry's Electronics had one (I grew up in Silicon Valley). It was sweet! :) Ran off the original power supply. Although looking back, I dunno maybe it was taxing the PSU a bit, but I didn't notice any ill effects back then. It was indeed a half height drive! :)

Of course, you could always get a SCSI card, which is much easier to find, and then get a SCSI to IDE adapter, like this one, which is Made in Britain rather than China :)

http://cf2scsi.com/

Some SCSI cards had their own BIOS so you could boot from them. :)
 
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We had a AST SixPack Plus which had a battery powered realtime clock and additional memory, taking our machine up to 640 KB of RAM :) You could install one of those and also an EMS card which would give you 1 MB of RAM, but then you're taking up two slots and the 5150 only had five. ANd you still need floppy controller, hd controller of some kind, video card, possibly sound card. :)
 
There was a Six Pack Premium which took the Six Pack design but increased extra memory to 1 MB or 2 MB with daughter card. There were other big memory EMS cards that also had RTC and parallel and serial ports but those were not big sellers during the 80s so finding one now may be challenging.
 
I will acquire 5150 soon ...
Lots of 5150 information at minuszerodegrees.net

Is there a way to install hard drive? Second power source is the only option?
First requirement is that you have the third revision of the BIOS on the motherboard.

Some people, wanting to fit a full-height drive drive, simply upgraded the 63W power supply.

Some half-height hard drives will not require that the 63W power supply be upgraded. It comes down to the power requirements of the drive, and what else is fitted to the 5150.

See modern options mentioned at the bottom of [here].

How much memory can be upgraded via ISA memory boards?

Conventional memory:

In the 5150, a requirement is that all four banks of motherboard RAM be populated before cards containing conventional memory are added.
Then the upper conventional memory limit is 544 KB if the first or second motherboard BIOS is fitted, or 640 KB if the third revision of motherboard BIOS is fitted.

Expanded memory:

Depends on the card added.

Does the memory need particular sizes for parity or does it just accept anything you put into it?
Motherboard: Very specific. See [here].
ISA cards: The card maker specifies RAM chip requirements. Refer to card's documentation.

Was the highest supported format DD floppy of 720kb? Any way to use HD floppies?
Answered at [here].
 
A 1" high scsi drive does fit nicely under the right-side floppy drive and is hardly noticeable.

5150 008.jpg5150 009.jpg5150 010.jpg
 
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