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BOOTSLOW -- slow down for self boot programs -- 1.00
Copyright (c) 1991 Alexander R. Pruss
May be freely distributed, modified and used provided that no copyright
messages are removed, and this sentence together with the next two are
always included in unmodified form. If you like this program a lot, you are
invited to show your appreciation by making a tax-deductible donation to
the Pro-Life or Anti-Abortion movement, but are under no obligation, moral
or otherwise to do so (especially if you disagree with the goals of this
movement.) There is no warranty; use at own risk.
There are many slowdown programs available, but this is the only
one I know of that can slow down a self-booting program, i.e. one
where you simply put the program disk in the computer and boot it.
Send comments, bug reports to:
pruss@unixg.ubc.ca (InterNet)
pruss@ria (UUCP)
PRUSS@UWOVAX (Bitnet)
1. Preparation
For BOOTSLOW to boot all PC-"compatible" computers (some of which like
the AT&T 6300 having a brain-dead interrupt 19), some information must
be known to the program about the conditions on boot-up. This
information may differ between systems and thus it must be newly
garnered on each system BOOTSLOW is to run on. This information must
also be regenerated after every hardware or BIOS upgrade.
You will need a PC compatible system with at least two drives (one
floppy, and the others can be RAM or hard), with about 16Kb of free
memory. Some of the utilities may crash in less memory.
1.1 WHIRR.COM: knowing which drive is which
You will have to know which DOS drive is which of your drives, and which
physical drive is which of your drives.
All the programs except for SLOW.COM make use of physical drives. For
convenience, they are called A,B,C,etc., referring to BIOS drives
0,1,2,etc. Note that since hard drives usually have numbers
greater than 127 this makes it impossible to access them. Usually the
physical drive letter will be the same as the usual DOS drive letter,
but not always. (Especially not if you have run ASSIGN, JOIN or SUBST,
and almost never for hard-drives.)
SLOW.COM uses logical drives, to let you boot special devices such as
hard-drives or bubble-drives. Each logical device is also referred to
by a DOS drive number 0,1,2,etc. for convenience denoted as a,b,c,etc.
If you did not use ASSIGN, JOIN, or SUBST then it is most likely these
letters are the same as the "usual" DOS drive letters.
To find which physical or DOS drive letter refers to which of your
drives, run
whirr
at the DOS prompt. You will get the display:
----
Disk Whirr Program.
(C) Copyright 1991 Alexander Pruss
Press an upper case letter to whirr a physical floppy, or a lower case letter
to whirr a DOS drive.
Press A,B,..., or a,b,c,..., or ESC to abort.
----
Pressing a capital letter A,B,C,etc. will quickly whirr the
corresponding physical drive. You should be able to tell which drive it
was by watching your disk indicator lights. Similarly, pressing a lower
case letter a,b,c,etc. will whirr (light up) the corresponding DOS
drive. This is a nondestructive test.
Try pressing a,b,c,d and A,B,C,D. If there is no disk in a drive, a
disk error will be signalled. Now remember the physical and DOS letters
for each drive. Press ESC to exit. Note that as aforementioned, you
will likely be unable to address hard-drives by physical letters.
1.2 BOOTSEC.BIN, MKBOOT.COM, MKTABLE.COM, BOOT.ITB: knowing your
configuration
You will need to do this once at the beginning, and henceforth after
every BIOS or hardware upgrade.
1.2.1 Making a special boot disk
Now, to garner the system configuration data, prepare a blank formatted
disk. (If it is not blank, the data will be lost.) Insert this disk in
one of your physical drives, and type at the DOS prompt (while in a
directory containing the BOOTSLOW distribution):
mkboot
If all goes well, you will be prompted for a physical drive letter.
Press the letter corresponding to the drive you put your blank formatted
disk in. The data (if any) on this disk will likely be destroyed, and
the file BOOTSEC.BIN will be installed on it. If you have a disk error,
try using a different disk or drive. You may instead press Ctrl-Break
to abort.
Your blank formatted disk has now become a special boot disk.
1.2.2 Booting it
Take this special boot disk and boot it. (Put it in a drive that is
normally checked at boot-up and reboot the computer, say by pressing
Ctrl-Alt-Delete.) If everything works, you will see on your screen:
----
Interrupt table recorder.
(C) Copyright 1991 Alexander Pruss
Choose physical floppy drive to save to: (A,B,etc.)
----
(Again, even more data on the disk will now be destroyed, so if the
special boot disk is not really blank and you realise you need the data,
quickly remove the disk, reboot your computer and run your favorite data
recovery program on it. It should not be too late.)
Press the physical drive letter the special boot disk is in. If all
goes well, you will get the message:
----
Saved!
Remove this disk and reboot with Ctrl-Alt-Del.
-----
Remove the special boot disk and reboot the system. The disk now
contains your systems initial interrupt table.
1.2.3 Grabbing information from the disk
After rebooting the system, go to your directory containing BOOTSLOW.
Insert the special boot disk again, and type
mktable
to get the message:
----
Interrupt table recorder.
(C) Copyright 1991 Alexander Pruss
Choose physical floppy drive to load data from: (A,B,etc.)
----
Press the physical drive letter where your special boot disk is. Drives
should whirr, and the message "Done!" should appear. You now have all
the necessary information saved in the file BOOT.ITB. You can now
recycle your special boot disk. I recommend you reformat it.
BOOTSLOW is now ready to slow games and other programs down.
2 Running SLOW.COM
SLOW.COM does all the work of slowing your computer down (after you
spent all the money on making it so fast...) In summary, you type:
slow [d] [factor]
and press the DOS drive letter containing the disk you wish to boot.
You wust be in the directory containing the BOOT.ITB file.
Normally the slowdown does not occur during disk access, but the logic
behind the detection of disk access may at times fail with the effect
that slowdown does not occur at all even not during disk access
(I have yet to actullay meet such a case, though.) In this case, (or
for some other reason), you can include the "d" flag which will make the
slowdown constant, even when the disk is being accessed.
factor is the slowdown factor, by default 200. The larger it is, the
slower your computer is.
2.1 How to do it
Find the disk you wish to boot at a lower speed. In the directory
containing BOOT.ITB, type:
slow
You will receive the message
----
Self-Booting Disk Slowdown.
(C) Copyright 1991 Alexander Pruss.
Choose DOS drive to boot: (A,B,C,etc.), ESC to abort.
----
Insert your booting disk (unless it is a hard-disk!) and press the DOS
drive letter of its drive. (Not necessarily the same as the usual DOS
letter, nor the same as the physical letter.) If thing are working you
will be told, "Booting..." and the disk will boot, with the computer
slowed down and robbed of 1Kb of memory. You can boot your main
hard-disk too, so you can load DOS. To return to the usual
configuration, reboot your system.
If you change your mind, you can hit ESC to abort.
You should look and see if the computer is slowed domn enough or too
much. You con control the amount of slowdown by typing:
slow factor
instead of just:
slow
where factor is the slowdown factor. The greater it is, the slower your
computer will be. By default factor is 200.
If you are having problems, try including the "d" flag as in:
slow d 300
or
slow d.
Note that if you use SLOW.COM to boot DOS then you can run SLOW.COM
again. The slowdown will NOT be cumulative, although the 1Kb of memory
use will be.
3 Testing
Not enough testing done. Tested and seems to work perfectly with Jump
Man (on floppy) and DOS 3.3 on hard-drive.
4 Bugs
Not enough testing done.
Some programs may crash in less than 16Kb of free memory.
Source not tested on MASM or versions of TASM other than 2.0.
I cannot figure out how to get it to work in conjunction with SIMCGA's
self-boot handler. But then, SIMCGA by itself should be a sufficient
slowdown!