A couple of months ago I bought a BBC Model B for reasons of nostalgia. It works fine and loads programs from the ROM as well as a couple of things on tape. This week, I bought a Cumana 5 1/4 disk drive and around 100 disks on eBay (from separate places).
The drive appears to work fine and searches when prompted, I am also able to enter the *CAT command and list the contents of every single disk. Unfortunately, whilst I can see what is on all the disks (leading me to think that the disk drive must be working) none of the programs load. I keep being given error messages such as “Bad Program” or Sector not found (20/02, 05/00, 04/07, 01/00).One which appeared slightly more hopeful seemed to load when hit SHIFT + BREAK, but once the disk loaded I had the word “CHANNEL” flickering down the screen continuously.
Something which occurred to me was whether the disks were a different type. I noticed that this drive does not have a 40/80 switch and wondered whether this could be why nothing is loading. But this leads me back to wondering why I can see the content for all of them… Could it be that the head is not as good as it was and that I need to take the drive apart and clean it? Or have the disks had it after the best part of 40 years in storage. I will say that they all look to have been well-kept and in very good condition for their age.
Any help on this would be much appreciated as this is currently on the edge of my understanding of the BBC Micro. My next step is to otherwise buy another drive and see if that works, but given their cost I would rather be sure that this what I should be doing!
This could be very much a problem of the disks vs drive. Although on the ZX Spectrum, I had the same problem:
I do have original HiSoft DEVPAC 3,5" floppy disk for OpusDiscovery. When I read it using regular DS/DS disk drive, I do see a directory with the files, amount of free space and so on, but I cannot load anything and get an error (Sector not found I guess). After examining the disk I have found out that the disk is single-side formatted but the system tries to read both sides thus yell an error (OpusDiscovery was originally shipped with a single side drives).
Welcome Henning. It could be the 40/80 thing. Perhaps you could show us what you see on the screen at boot, and what you see with a *CAT? If an 80 track disk is being read by a 40 track drive, or vice versa, I think it could be that the first track might be readable but an attempt to read another track will land in the wrong place. (Reading even the first track of an 80 track disk with a 40 track drive would be unreliable, I think.)
(If we can’t solve the problem here, the nice people over on the stardot forums are very likely to be able to help.)
I’d also go with the 40/80 thing too. Maybe the DFS ROM has a double step command? Some did…
Also worth while cleaning the drive heads - unless the unit was already cleaned when you bought it.
And watch out for dirty discs - some disks I’ve found in the boxes of old/inherited stuff I have are very poor, especially if they were stored in damp conditions.
Hi Henning,
Usually this is because the stepper moter is jammed. When you put a new disk in or do a *. you should here the click click click as it goes through the tracks. If not it may be what I said and you should open the drive and give it some tender loving care like a gentle wiggle and perhaps a tiny tiny bit of a very light oil. Remember get that on the head and it will cause terrible problems.
This is my thought.
Also get ready for the capacitor exploding if it hasn’t been changed already. They are on the power supply of BBC computers but also in the Cumana drives and are best replaced. As far as I am aware they don’t cause secondary problems when they go other than to make some smoke and things.