rsilvers@hawk.ulowell.edu (Robert Silvers.) (05/09/88)
People have been talking about using the fast file system with
floppy drives. How about a different way to speed up the system, while
keeping compatability with the old AmigaDOS format? The main bottleneck in the
existing system is the directory, which is scattered all over the disk.
This, as we all know very well, takes lots of time to scan. Why not just
have the directory on one or two tracks, like most other micros? This would
dramatically speed up the system--instead of taking thirty seconds to scan a
large directory, it would only take two "disk clicks"-less than one second!
This could still be compatible, as the system could still write the
directory in the same format, except it just happens to be on one track.
The old DOS would read this as it would read any other disk. When writing
to the disk, the new DOS would avoid these "reserved" tracks, using them only
for writing directory information. If it finds a disk with a "scattered"
directory, it will only do its best to keep the directory in one place
(that's all it can do.) This is to say that new disks used under the new
DOS would have a faster, single-track directory, while older disks would still
act the same.
Since each track is about 11K, reserving one track would make that much
disk space unavailable for data storage. Out of 880K, that is almost
unnoticeable. I'd say this tiny loss is worth the great increase in speed!
Another restriction would be the number of filenames per disk, but with 11K
(22K if two tracks are used) of directory space, most users would never
notice. High speed and cross-version compatibility--what do you have to lose?
One other thing: the DOS could have an option, similar to AddBuffers,
where the whole directory could be read into memory when a new-format disk
is inserted into the drive. Two "clicks," and the directory is in memory.
Any ideas?
- Greg Searle
Robert Silvers.
Box #1003 University of Lowell.
Lowell Ma, 01854
(617) 452-8823 Rm. 322 "Live free or live in Massachusetts."