28 Jul
2003
28 Jul
'03
2:08 p.m.
It was thus said that the Great Bob Shannon once stated:
Files will be allocated a fixed ammount of space, similar to a track per
file as in Northstar DOS.
A file can be smaller that its allocated space, and grow. If the file
needs to be larger than its allocated
space, it moves to the end of the disk, and a second file is created as
an 'extent' to the first file.
Files are always linear, so the HP DCPC control code remains simple.
I have a few questions then. 1) What is the smallest amount of data that
can be transferred? The largest amount? Any restrictions on data
placement? (for instance, on old PCs, you could only use the lower 1M (16M
for 286 or better) of RAM, the smallest amount was 512 bytes, largest 64k
(128k for 286 or better) but you could not cross a 64k boundary) How much
space can you set aside for disk buffering?
I think people had to think their software designs
through more
carefully when they only has 32K. Now that
a machine with 32 meg is frowned upon, file systems have become a very
different thing in terms of implementation.
Another question: about how big do you expect the average file to be?
And what type of files do you expect there to be?
-spc (Interesting problem ... )