Sunday brain tickler

[Chuck Guzis]

On 01/08/2017 06:25 PM, allison wrote:

> I haven't ground on what it may be but there are four likely 
> directory/catalog cases.


I've certainly seen my share of various filesystems.  In fact, I can
laboriously reconstruct the original files, there being only 70 1200
byte blocks on the disk.  I thought that having a file name might be useful.

I'm just a bit weary of deciphering this one-off and can't get my mind
in the right frame to paw through the directory structure.

But I put it to you that there exactly 72 (or 71) entries in this list
and there are exactly 70 1200-byte blocks--and, make no mistake, they
are 1200-byte blocks with a definite format--a header followed by text.
Short blocks are denoted by a control character sequence, after which
old data to the end of the block may be found.  So it's quite possible
to splice the bits together into complete documents.

But that's cheating--I'd like to understand how the first block
directory dictates the relationship between blocks and any file names.

So let's look at the directory again--note the 11th bytes all either
have values less than 70 (decimal).  I'm guessing that that's a forward
link to the next block--note that 7F is the only out-of-range value
present in this column.  I suspect that this is the end-of-file marker.

This is all guessing at this point.

--Chuck