ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/UTILITY/DISK/SDF21.ZIP/SDF.DOC

Text File | 1987-11-16 | 5.8 KB | 142 lines

SDF : Speedy Disk Formatter.
----------------------------

If you have got a genuine PC or PC/XT or a compatible, this program might
be useful to you for fast formatting 360K disks.

If you have retrofitted a 3.5" drive, this program might be even more
useful, for formatting both 360K and 720K disks.

Some bare facts :
---------------

- Formatting a 3.5" floppy under DOS 3.2 or 3.3 takes 3'22 on my CHINON drive.
- Copying about 200,000 bytes over from a 5 1/4 floppy to the 3.5" takes 2'53.

These times involve either DOS 3.2 with DRIVPARM=/D:1 in the CONFIG.SYS file,
or DOS 3.3 with DEVICE=DRIVER.SYS /D:1 in the same CONFIG.SYS file.

Now, what is the reason for having DRIVPARM or DRIVER.SYS ?

As far as I know, they are only used at FORMAT time, so that the
formatting program knows which kind of drive is installed. When accessing
a formatted disk, DOS decides after peeking at the Media Descriptor byte
what kind of diskette it has to deal with, and DRIVPARM or DRIVER.SYS are
no longer required.

Try the following :

1. Format a 720K disk with your current CONFIG.SYS (including DRIVPARM=
   or DRIVER.SYS), and FORMAT.COM.
2. Copy about 200,000 bytes of data to the diskette.
3. Time the operation. Depending on how many files make up the 200,000 bytes,
   (i.e. how many directory updates will be required), the copy might take
   2'53, as in my case.

NOW,

4. Remove the DRIVPARM= or DRIVER.SYS entry in your CONFIG.SYS file,
   and REBOOT your computer.
5. Delete the files that had been copied over in step 2,
6. Do the same copy again.
7. Time it. In my case, copying took 2'04, which is not far from 30 %
   improvement.
8. Notice that DOS didn't object to your having a 720K formatted disk in
   the drive without having been told so in the CONFIG.SYS. The 0F9h media
   descriptor it found on the disk is sufficient for DOS to know how it
   should handle it.

SO,

It looks to me as though these DRIVPARM= or DRIVER.SYS are there only for
two purposes :

1. Let FORMAT know what to to with these drives,
2. Be in your legs afterwards to slow your system down.

THEN

I decided that DRIVPARM= or DRIVER.SYS were not needed if one had the
correct program to format diskettes at the required capacity, and
that speed could be added as a bonus.

Finding fast formatters is no problem, there are many good ones on CIS,
but I found only one who knew about 3.5" floppies : QDR by V. Buerg.

I tried it, and found out it had bugs in handling the 3 sector FATs used
on 720K disks (does not clear the third FAT sector).

I finally ended up writing my own formatter, with two goals in mind :

Support for 3.5" 720K disks, and SPEED.

This is what SDF has been designed for.

SDF formats a 720K disk in 1'40, with verification, or 1'08 without
verification.

By the way, FLOP2 (which is my fix to the original FLOP) speeds up floppies
even more : the 200,000 bytes copy takes only 1'09 on my system (8 Mz clone),
when set FLOP2 is set to FAst. I included FAST2 with the SDF package, so
you can squeeze any clock tick out of your disk accesses.

A word of caution : both programs fiddle with pseudo interrupt 1Eh, which
describes some disks parameters (motor start up time, heads step rate, a.o.).

The parameters these programs are modifying are usually overly conservative
as set by DOS. Dramatic speed improvement can be achieved by carefully tuning
these parameters. I strongly suggest you have a look at the source codes
before trying to modify bluntly the values used. A short description of
these parameters, known as the Disk Base Parameters Table can be found in
Norton's book "Programmer's guide to the IBM PC" pp. 196-198 (Microsoft Press).
Also, beware that some systems will be perfectly happy with Motor Start Up
time (in 1/8 seconds) set to 0, whilst others will irremediably hang (that
is the case for my Olivetti M24 / ATT 6300 at work).

Using SDF.
---------

SDF is auto-documenting, i.e.  if you type SDF at the DOS prompt, you
will be given a usage message.  A drive spec MUST be specified, and is
A: or B:, and some optional switches may follow.  The switches ares /Q
to format in Quad Density (80 tracks, 9 sectors per track, 720K
capacity), default is Dual Density (40 tracks, 9 sec/trk, 360K), and /V
to force a Verify of the just formatted disk (default is NO verify,
assuming that everybody buys good grade diskettes, and that 3.5" disks
are of better quality).

SDF will tell how many K-bytes (1024 bytes) are available in the file
area, and prompt for another diskette with a whistle (I like that one -
idea picked up from DBLFORM).

The newly formatted diskette will have a label to remind you of where
and how it was formatted e.g. "SDF-B:+Q+V-" means the disk was formatted
in drive B:, with /Quad density and /Verified. Running CHKDSK on the disk
will also show the date and time the disk was formatted.

The last word. In the quest for capacity, SDF only marks bad clusters, and
not the whole track as does FORMAT when it encounters a bad sector.

WHAT SDF DOESN'T DO :
-------------------
- SDF is currently useless for 1.2 MB drives as found on PC AT's. I might
  think of adding support for these drives if demand exists.

- SDF does not allow for the disk to contain a system. This is partly due
  to laziness, and partly due to logic : creating a disk with a system is
  an unfrequent task. If you require such a disk, go back to FORMAT for
  that instance. In any case, trying to boot from a SDF formatted disk
  gives an explicit message to the screen, and allow further booting
  from another floppy or hard disk at the hit of a key.

Any hint, comment and suggestion welcome.

Enjoy, and get rid of DRIVPARM and DRIVER.SYS as soon as possible.

Jacques Pierson        CIS 76446,1516        November 16,1987
Computer Center
University of Namur
Rue Grandgagnage 21
B-5000 NAMUR (Belgium)