Author Topic: pcw 8512 B drive differences  (Read 487 times)

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Offline geebus

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pcw 8512 B drive differences
« on: 17:37, 05 August 20 »
Hi folks,Just wondering if anyone can tell me what the difference (apart from the drive capacity and head count) is between the a and b drive.
The reason I'm asking is that I'm trying to make the a drive in my 8256 into a b drive.
I'm using a gotek for the a drive and have cut the trace on the old a drive's pcb that tells the computer that it's a, then soldered the line to make it a b drive in on it's place instead.
Should i just leave the lines (a or b) unsoldered so that it's just "floating?" or is there something else i'm missing?
When i'm in CP/M and try access b: it gives me a BDOS function = 14it does try to access the drive though.
« Last Edit: 17:44, 05 August 20 by geebus »

Offline GeoffB17

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Re: pcw 8512 B drive differences
« Reply #1 on: 18:14, 05 August 20 »
Hello,

Which version of the system (JxxCPM3.EMS) are you using.?

At least part of the problem may be to do with the system.   The different versions may have something in the code that expects that A: is a single sided 173k drive, and B: is a double sided 730k.   It will complain if this is not so, or will have trouble accessing the disk, or both.

For a while, while my A: drive was broken, I was using my 360k B: drive as A: using single sided floppy disks to boot from.   With advice from John Elliott, I was able to 'patch' the very old 1.1 system file to be helpful, but later versions were not so obliging.   You've got the other side of the problem, i.e. the system will be seeing the B: drive as single sided when it OUGHT to be double sided and this will generate an error.

This is there for your protection, regarding getting A: and B: disks the wrong way around, but the test has been done in different ways over different versions and sometimes it's not as helpful as it might be.

Later versions of the system that use .FID mods can have a B180.FID file that may help.  I think I'll have such a file somewhere.

BDOS Function 14 is the 'Select Disk' function, so the error is telling you the disk isn't correct.   Which I assume IS because it's SS when it ought to be DS.   I don't think it's anything to do with the actual drive, it's the disk it's trying to read.

I've looked through some of my files, and found a B180.FIB.   The text in this says that B: is a 3" 180k disk.   This may help, but I thought that the .FIB files were just to to with the disk speed (?) parameters, but maybe not.

Geoff
« Last Edit: 18:31, 05 August 20 by GeoffB17 »

Offline geebus

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Re: pcw 8512 B drive differences
« Reply #2 on: 20:16, 05 August 20 »
Looks like I've got j11cpm3.
I've had a quick Google for the b180.fib and found more topics on cpcwiki with people having the exact same issue.
However, can't find the fib file anywhere yet.
I shall continue the search as it's only just began.
« Last Edit: 20:18, 05 August 20 by geebus »

Offline GeoffB17

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Re: pcw 8512 B drive differences
« Reply #3 on: 20:32, 05 August 20 »
Hello,

Sorry, but it's more complicated than that!

There are two J11cpm3 variants, one is a VERY old version, actually system 1.1 (as shown on the screen at startup) this would be an .EMS file, then there's system version 1.11, this would be an .EMT file.

Actually, neither of these would support .FIB/.FID files.   For this, you need system 1.07H (not 1.7) or something from 1.15 and after.   Then there's the problem that 1.15 (and after ??) seem to have a problem with Gotek, so you'd be better to try the 1.07H which seems to avoid the Gotek problem, but still supports the .FIB/.FID  files.

I can just pack the 1.07H and the B180.FIB into a .zip for you and you can give them a try.  I cannot promise that this will sort things, but if it does something it may suggest what else to try.  Hopefully another message to follow this?

Geoff

Offline GeoffB17

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Re: pcw 8512 B drive differences
« Reply #4 on: 21:05, 05 August 20 »
Files attached.

The file J17cpm3.ems is actually j17hcpm3 - that's what it should announce on loading.  If it doesn't, I've got something mixed up.

The file B180.FIB shows the right message it it, but I'm not too clear what difference the .FIB or .FID makes, so if .FIB does not work, try rename to .FID and see if that's any better.

Geoff

Offline geebus

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Re: pcw 8512 B drive differences
« Reply #5 on: 21:31, 05 August 20 »
Thanks Geoff,looks like there's not enough space on the disk for both of those files after removing the J11cpm3.
I'm continuing my google.Thanks for attaching those!

Offline GeoffB17

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Re: pcw 8512 B drive differences
« Reply #6 on: 22:38, 05 August 20 »
Oh?

Disk must have been near full then?   The .EMS file is only slightly bigger that the previous one, and the .FIB is only 400 bytes.  Or so.  Surely there was something you could remove, even if temporarily, to see if this solves the problem?

Geoff

Offline geebus

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Re: pcw 8512 B drive differences
« Reply #7 on: 11:11, 06 August 20 »
Yeah I was thinking of doing just that, however I'm not entirely sure what is best to remove to test it out. I could just start removing parts and testing it seeing as it's done via virtual disks and a gotek.

Offline geebus

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Re: pcw 8512 B drive differences
« Reply #8 on: 14:24, 06 August 20 »
Managed to get the patch to work using J15CPM3.EMS
It now shows the text "180k 3 inch drive" but still can't access it haha!
This is proving to be a lot more hassle than I thought it would be.