File copy versus disk cluster size

[Hein van den Heuvel]

Argh... I wrote 'header' but intended 'prologue'.
That would be the 'internal header', or VBN 1.

John McL, Relative file are organized in BUCKETS and therefore is is utterly irrelevant whether the record size has a special value.

Yes you can SET FILE/ATTR=EBK=xxx for a relative file.
RMS itself will ignore and read up until the prologue EOF.
If you then truncate, RMS will silently stop reading at the HIGH (allocated) block.

ANAL/RMS will complain. For example:
$ dir/size=all tmp.new.
TMP.NEW;1 2/6
$ anal/rms tmp.new
:
End-of-File VBN: 10
Prolog Version: 1
*** Attempt to read block with invalid VBN 6.
Unrecoverable error encountered in structure of file.


Hein.

[John Symmonds]

Ok here's what I've learned so far:

1) We should use BACKUP to copy files like this whenever possible.
2) Our file is not very well thought-out.
3) RMS fixes the file system EOF when the file is opened for shared access.
4) I've got a lot of reading to do in my spare time to understand some of this.

Also, I have to spend some time to understand how this file is used in our system.
Thanks a LOT for all the info.

Cheers,
John