5.25" drive - can it be used on MSX2? -- crazy talk maybe, please forgive

Supporter (16)

01-02-2011, 22:05

I have an 8250 with 1 x doublesided 3.5". works great.

I also have an old CP/M computer that needs a way to transfer media from a PC, onto a 5.25" floppy disk.

my PC's disk controller, like so many recent /this decades' PC's, absolutely cannot write to a low density disk like a 5.25".

So heres my thoughts:

I have CP/M on floppy for MSX2.

if I boot from the 3.5" A drive, could I connect a PC 5.25" floppy to the MSX2 as drive B and read/ write to it? If it worked, I could possibly find a way transfer onto 5.25 floppy (notwithstanding details at this point and that mosty CP/M systems had differeing formats) but is it at least possible to get the hardware working?

anything I'd need to do to the cables?

does the 8250 have a B driver connector? (i think it does)

are there any custom format or file writing software for MSX2? ie different numbers of sectors, tracks, bytes per sector etc. please help.

I dont mind if I have to use msxdos or CP/M to do it..

is this madness talking?

thanks for thoughts all

iain

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By RetroTechie

Paragon (1563)

02-02-2011, 18:47

Some (external) diskdrives used for MSX were 5.25", and I've had a 40-track, single sided 5.25" drive hooked up to a 3.5" floppy interface once. 160 or 180KB formatted IIRC (possibly with some bootsector editing ). This worked fine. So either way: physically it's possible (not necessarily easy! depending on drive / interface used).

But a more difficult problem might be the logical format used for CP/M disks. AFAIK there were many custom formats in the CP/M world, and CP/M for MSX may be able to run CP/M software but not know about those many/custom disk formats.

It might be easier to find an old PC with 5.25" drive, read floppy images, and (with floppy images transferred to normal PC) use some specialized tools for reading those disk images. Or do some research on how people used to transfer software from CP/M to PC/DOS systems. Or if it's remotely popular software you want to transfer (as opposed to datafiles / your own work): determine program + version & locate copy on an ftp site somewhere...

By SLotman

Paragon (1242)

02-02-2011, 20:20

Every disk drive on Brazil were 5.25"
We had even drives adapted to write 720kb on them. Some had switches, to change them back and forth from 360kb to 720kb.
I still have some of them around... but they don't work anymore

No extra hardware needed, just connect them (you can even use PC cables for that) on the disk interface and it will work.

By iainjh

Supporter (16)

02-02-2011, 23:55

Thanks

I shall go ahead and try it!

Anyone got any leads re writing custom formats on max please? Any disk utils?

Cheers!

By mohai

Paragon (1031)

03-02-2011, 11:25

Be warned that regular DISKROM is not able to handle Single Density format (180 K).
You can connect a 5,1/4" drive to 8250. Just find suitable cable and configure Disk Select jumper on your drive. Then, you will be able to handle single or double sided disks, but only DD (Double density).
To read a Simple Density disk, you will need a drive with a diskrom capable of it. AVT and Daewoo drives can help you.

By mohai

Paragon (1031)

03-02-2011, 12:19

No extra hardware needed, just connect them (you can even use PC cables for that) on the disk interface and it will work.

Off topic:
Hello.
I have an AVT-550 drive (it is a Daewoo DPF-550). I think it is similar to some Brazilian drives (it is controlled by port 0xD0).
I am trying to cahnge to 3,5" and 720 KB.
Could you send me suitable DISKROM?

(mohaimsx (at) gmail.com)

Obrigado!

By iainjh

Supporter (16)

03-02-2011, 16:42

thanks Mohai

what specifically do I need to handle single density as well then? I have a 5.25 single density drive.

I have a fast diskrom in the 8250, thats all I know!

By tcruise

Master (135)

05-02-2011, 00:08

Have a look at the Spectravideo 738 Roms, as it came with CPM and a 5 1/4" drive was available with software to read/write/copy information from about 30 different formats. I used to have one of the drives, but for the life of me I have not been able to find it. I really can't see myself selling that, so it must be somewhere.

By iainjh

Supporter (16)

06-02-2011, 00:34

Thanks for the info!

I can get an EPROM blown v easily.. Does that mean, if i get a 738 bios ( is it the bios I need or diskrom or..which specific rom? Where from? ) I can swap that into my 8250 msx2 and it'll boot and off I go?

Guess I just need the floppy after that?

Thanks again for your info and help and sorry for newb questions.. else I'll just assume the wrong thing..

Cheers!

Iain

By iainjh

Supporter (16)

06-02-2011, 01:21

Can't seem to edit my last post -

But here - http://retrocomputacion.com/yabbfiles/Attachments/SVI_707_Disk_Drive_User_s_Manual.pdf

Very interesting program, I assume you were recalling " Copy707?"
On page 5-2 of that it lists 5 other formats so I do have 2 more questions please:

Do you reckon there was a later version with more formats?

It seems to only write to double density anyway - my old cp/m stuff is low density,( yes, LOW density 128 byte sectors :) )

Any ideas if the msx2 can write even with the 738 bios to low density before I follow this rabbit hole?

Cheers again however the outcome! Thanks !

Iain

By tcruise

Master (135)

06-02-2011, 10:48

I do know the unit was produced by the guys from Northern Tasmania i.e (SAUG), they being old school CPM guys at the time, so it wasn't official Spectravideo software. I think it may have been some older CPM software that they ported.
I have not had time to have another look for the drive and software during this weekend just gone, so all I can promise is that I will have another look during the week, but probably next weekend. If I can find the software disk I will try and get an image off it (as long as the disk still reads - cross fingers).
The Spectravideo 738 was fully able to be upgraded to a MSX 2 machine, as it already had the correct video processor, so there is a good chance that the disk bios will work with other MSX 2 hardware. I'm not that much of a hardware guy anymore, so perhaps someone else may be able to shed some light.
The drive was just a 5 1/4" cable that connected to the driver expansion port of the 738, and the CPM software came with it.
I did get an original updated BIOS from the some guys, that allowed the single sided 3 1/2 drive to be upgraded to double sided and fixed the initial format disk bug, but this was much earlier than getting the drive.
I mostly used the drive to transfer between my original Spectravideo software over to the MSX machine.