"Directory input error" on a RL02k under RT11, is that cartridge now scrap?

[braids]

Hi all,

I has a problem with a RL02 cartridge carrying RT11 V4. The directory will be shown with the DIR command but the files are no longer accessible. When i make an init/badblocks then a table with foul blocks, 20(decimal) the lowest will be displayed and then the error "Directory input error". I believe on the RL02 the formatting is not on the disk but mechanically solved. I think the magnetic layer is worn. Is there a ability to use this disk under RT11 furthermore (i.e. with quirks) / under an other OS / fixed blocks / or is it now scrap?


Best Thanks,

Braids

 

[Gary C]

isn't it embedded servo ?

if the info in the servo tracks are degraded, you can't do anything to remake them in a drive

 

[Ian Hammond]

Braids,

It's unclear whether the disk can be salvaged in part or at all.

I'm assuming that you still have some RL02 disk packs that are still functional, which thus localizes the problem to the disk volume rather than the controller.

INIT/BAD generates "Directory input error" messages when its trying to associate files with detected bad blocks. To do that it must scan the directory. Block 20(10) is usually an RL02 directory block which probably explains the error message. Initializing the disk with few directory segments *might* circumvent this issue. You will, of course, lose all the data on the disk.

RT-11 directories begin at block six. Each directory segment takes up two blocks. Thus, theoretically you should have space for seven directory segments (6+(7*2)=20). Thus INIT/SEGMENTS=7 DL0: will exclude block 20(10) from the directory. Following that you can try the INIT/BAD command again. At the very least it might be possible to get a completed list of all the bad blocks so that you can see the extent of the damage.

RL02 disks usually have 31(10) directory segments, each of which can hold up to 72 entries, although they typically hold about half that, so there will be substantially fewer directory entries available. You could solve that problem with later versions of RT-11 that support Logical Disks by creating logical disks that enclose the good areas of the disk.

All that said, there are a couple of things that don't make sense to me.

1. If the directory itself does have bad blocks then directory listings of the RL02 should fail.
2. I don't understand why at least some of the files early in the directory aren't accessible, unless of course there are many, many bad blocks.

Ian

 

[wa2flq]

Commands you may want to consder

DIR/BAD to scan for bad blocks
COPY/IMAGE/IGNORE (RT-11 V4?)
FORMAT/VERIFY/PATTERN (destructive)

 

[braids]

I have tried an init/segments:7 and the error was coming too. I've also ordered a RL02K. Format isn't working under RT11V4, i will try them with a newer version back on the 11/73. If there has no effect i will try to use this cartridge under SOL11 (a standalone FORTH derivate, requires EIS) with a driver that will start at a higher track and stream-only data holding