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MS DOS 3.31, IBM 5150, and a floppy drive question

br44

br44

Experienced Member
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Hello all

So as some of you might have noticed in another post I made, I have recently acquired a minty IBM 5150. Its in great shape and came with a ton of cool hardware installed. So of course the next issue is getting data onto this computer from a modern computer. I know I could install a compact flash dealie in there but I want to keep this computer relatively close to its era. So I have decided to mess with floppies.

So I have been looking around trying to find out what options I have in that department. I waffled back and forth between either installing a 5.25 drive in the modern computer.... or installing a 3.5'' in the IBM. From what I have read it seems it would be easier and cheaper to install the 3.5'' floppy in the IBM. So this leads me to compatibility issues. I have read conflicting information on whether an original IBM 5150 will accept a 1.44mb drive or if I have to stick with 720k. Some people claim that the 5150 will only work with strictly 720k drives... others say it will work with 1.44mb drives but it will only function in 720k mode. Others say it will have issues either reading, writing, or formatting. Still others bring up issues talking about what version of DOS you are running... many saying you should have at least DOS 3.30. There is also talk about something called Driver.sys

Do does anyone have first hand experience doing what I am trying to do? This is the setup.

the "modern" computer is a compaq presario 7478 which has a AMD k6-2 in it. (Hail to the King BABY :cool: )

I would like to pull files off of ^^^ and put them on an

IBM 5150 which is currently running MS DOS 3.31. It has a half height 40mb HDD and a speedup board made by PCSG. It has a single open slot on the front that is half height.

am I being stupid and over complicating this? I am trying to keep cost down. I already have a big pile of 3.5'' floppies but I do not own any 5.25''.
 
br44 said:
Some people claim that the 5150 will only work with strictly 720k drives... others say it will work with 1.44mb drives but it will only function in 720k mode. Others say it will have issues either reading, writing, or formatting. Still others bring up issues talking about what version of DOS you are running... many saying you should have at least DOS 3.30. There is also talk about something called Driver.sys
Click to expand...
1.44M drives postdate the IBM 5150 and the versions of DOS of the time. To support new hardware, both hardware and software (DOS and BIOS) need to be considered in the 'what new bits do I need to support the new technology' question.

I have listed the 1.44M drive options for the IBM 5150 at [here].

For example, the Backpack 3.5" external drive is a nice option (and you do not need to modify your 5150 [apart from adding a driver]).

That and lots of other IBM 5150 information is at http://minuszerodegrees.net/
 
If you really want to keep the machine as original as possible then you might consider putting a 360k 5.25" drive in that K6 system (first check that it can take two drives, it should support 360k) or with a Kroflux/Supercard pro.

If you want to add a 3.5" drive, you can attach a 1.4mb drive to the existing low density controller and use it as 720k. If you choose to use a current computer with a USB floppy drive to exchange data, be aware that some USB 3.5" floppy drives to not support 720k.

If you really want 1.44mb media in the system, you will need an 8-bit XT high density controller card. These exist, but are uncommon and sell for quite a bit on eBay.

DOS 3.3 or higher will work fine with 720k and 1.44mb disks (if you have the appropriate controller.) 8-bit XT high density controller cards add their own BIOS so the system fully supports 720k/1.2mb/1.44mb with no modifications. With the stock low density controller you need to add driver.sys (dos 3.3 or lower) or add the DRIVPARM statement to your config.sys. That change is really only needed for formatting disks, and they should still read and write fine without that.
 
I do not necessarily need to use a 1.44mb drive. If I stick a 1.44 drive into the 5150 and it reads as a 720k that is perfectly acceptable to me. If that happened I would use my small pile of 720k floppies in my k6-2 system to transfer the data. When I said I wanted to keep the IBM "original" that meant I wanted to use the form of technology that would have existed back then (floppies of any type). No compact flash or floppy emulators.

so alright guys thanks for confirming what I thought. This was helpful... especially that link above.
 
It's interesting that the "authentic" people have no interest in the single-sided 5.25" drives. DOS 1.x gave you all of 160KB per disk with those. If you had a fully-populated 5150 "A" model with 64KB, even simple disk copying got interesting.

Must be the same as the Osborne 1 users not liking the original, what 90KB, per disk...
 
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Well you have another alternative to keep that computer close to its era: use a serial/parallel file transfer utility. There are serveral free or commercial. A quick list:

* PC Magazine ZCOPY https://books.google.es/books?id=9w...AEIGjAA#v=onepage&q=pc magazine zcopy&f=false
* The Brooklyn Bridge (very common in mid-80s)
* Laplink
* Fastlynx
* ZIP
* ...

and you only need a null modem cable that can be easyly adquired or done.
 
Since the Compaq has serial and parallel ports why not use LapLink to transfer the data between machines? It's simple, easy and fast. FWIW, parallel is faster than serial but both work fine.
 
Chuck(G) said:
It's interesting that the "authentic" people have no interest in the single-sided 5.25" drives. DOS 1.x gave you all of 160KB per disk with those. If you had a fully-populated 5150 "A" model with 64KB, even simple disk copying got interesting.

Must be the same as the Osborne 1 users not liking the original, what 90KB, per disk...
Click to expand...

How do you come to that conclusion? I consider myself "authentic" when it comes to using my systems, but by "authentic" I refer to using my system with what it has available for me to use.

I don't think it has anything to do with a lack of interest it's just simply the hardware you have in front of you to use. You seem to be suggesting that it's strange an "authentic" person hasn't thrown away his 5150 Model "B" for a Model "A" so he can get that true authentic feel. I know IBM PC/XT's are still quite easy to find in the US, but we aren't exactly tripping over them down here and I'm sure it's the same in plenty of other places around the world for going "truly authentic" to be an option.
 
"Authentic" for the time would be a Model A with 64K (maxed out), running DOS 1.1 and either one or two 160K drives. That's what was available in 1983. How many IBM collectors on this list have exactly that combination? Most, I suspect have been upgraded.
 
my 5150 is not a model A

and since the high density 1.44mb 3.50'' floppies came into being in 1986 i do not consider it unreasonable someone would have had one.

Furthermore i am trying to recreate the experiences I would have had as a kid. Since I was born in 1993 I experienced the early IBM computers long after they had come and gone. I am not even absolutely sure which version of the IBM i played games on because I was so young.
 
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