DOS ain't dead

"SST - Seek Stopper" -- Caching Needed, Too! (Developers)

posted by Jack , Fresno, California USA, 12.03.2010, 22:35

> On Wikipedia I found a link to the "SST - Seek Stopper Hard Disk
> Optimizer", a very early defrag utility, which has been released
> to the public domain in 2005 (?) ...

I have used the 1998 "Diskeeper" for Windows/NT for over 10 years,
which functions similarly to "SST".

Disk "defragmenter" programs can gain a bit faster hard-disk speed
by re-arranging data, so no "big" seeks are necessary when reading
existing files. All sectors of a file are on the disk in "linear
order", thus extra seeks are avoided.

Disk "defragmenters" do NOT help when writing files, as DOS cannot
guarantee new files' sectors are written linearly. DOS will give
files the next "free" group of FAT-table sectors, which themselves
may not be in linear order! So multiple output files are usually
written "fragmented", i.e. part of file "A", then part of file "B"
etc.

Also, "defragmenters" made sense in 1986, when hard-disks had seek
times of about 5-msec on 1-track seeks and 30- to 50-msec averages
for the entire hard-disk. These times are 1-msec and 4.5-msec on
"modern" hard-disk drives offered now!

So, a "defragmenter" gets you only so far in improving disk speed.

After a disk has been defragmented, one still needs a disk caching
program with DOS. DOS must still access the disk's directory and
FAT tables for any file, and DOS is written for only single-sector
directory I-O. Reading/writing disks one sector at a time is NOT
efficient, as it LOSES a disk revolution between each sector pair!
Hard disks CAN do multi-sector I-O, but DOS still has its original
1981 "El Cheapo" directory handling, which slows EVERYTHING down!!

Such accesses are mostly eliminated if UIDE (or LBAcache/CDRcache,
if appropriate) is used to CACHE directory and FAT data! Actual
file data will ALSO be cached, and thus a DOS system will run even
faster. FAT, directory, or file data that is "in cache" requires
only a fast move from XMS memory (the cache), NOT a slow "physical
access" of the hard-disk, diskette, or CD/DVD drive.

DOS users should have BOTH a "defragmenter" AND a caching program!

---
(Account disabled on user's request.)

Complete thread:

• "SST - Seek Stopper Hard Disk Optimizer" found - rr, 08.03.2010, 22:36 (Developers)
  • "SST - Seek Stopper Hard Disk Optimizer" found - Arjay, 11.03.2010, 16:13
    • "SST - Seek Stopper Hard Disk Optimizer" found - Rugxulo, 11.03.2010, 19:25
      • "SST - Seek Stopper Hard Disk Optimizer" found - RayeR, 12.03.2010, 02:13
  • "SST - Seek Stopper" -- Caching Needed, Too! - Jack, 12.03.2010, 22:35