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TRACKPIC.DOC
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1991-09-24
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11KB
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version 1.1
(C) 1991 by Thomas Opheys
1. WHAT'S THE USE OF TRACKPIC?
You know what happens when you reboot your computer and there is a disk
without system in your boot drive... Usually, a simple message like
" Non-System disk or disk error
Replace and press any key when ready "
(MS-DOS 5.0)
is displayed on your screen.
Imagine being the boot program of that disk. This little friend is just
sitting in sector 0, waiting for a user trying to boot his disk. And instead
of doing a demanding job then, he just types this dull message. You can
imagine that his life is only frustrating... often, this ends in attempted
suicide!
Help him!
TrackPic changes the boot sector of non-system disks. If you unintentionally
try to boot such a disk, a 320x200x256 VGA picture is displayed and informs
you in a much nicer way of the boot problem. The picture is stored on tracks
not used by DOS. You can use TrackPic with every formatted disk and use your
own pictures - without losing data or a single byte of disk space!
2. WHAT DISKS/DRIVES CAN TRACKPIC USE?
TrackPic works on every standard MS-DOS formatted 360k, 720k, 1.2MB or
1.44 MB disk. If TrackPic detects a non-standard number of sides, tracks,
sectors per track or sector length, the disk is rejected.
The disk can be empty or full of files - Trackpic only manipulates the
boot sector and formats tracks never used by DOS. No other system or data
areas of the disk are changed and from the DOS view, the disk is the same
as before. Nothing does happen to your data.
TrackPic uses tracks that lie behind the ones normally used by DOS.
If you use disks with smaller capacities (360k, 720k), it is possible that
even though TrackPic compresses the picture, it won't fit on the disk.
You can override the safe track limit with the /o option if you think your
drive supports more than the number of tracks given below. But this is
a bit dangerous and could damage your drive.
Format Tracks Bytes Comment If picture does not fit
------- ------ ------ -------------------------- -----------------------
1.44 MB 80-83 73728 every picture can be used -
1.2 MB 80-83 61440 ~99% of all pictures fit cut 10-15 lines
720k 80-83 36864 ~75% of all pictures fit cut some lines
360k 40-41 18432 ~40% of all pictures fit use less detailed pictures
If you copy a disk with a TrackPic boot sector using a normal DOS disk copy
program, the picture will not be copied because it is out of DOS's reach.
The copy of the disk will display the text mode message when booted.
Did I say that the disk shouldn't be write protected???
3. OTHER REQUIREMENTS
To install the TrackPic boot sector and the picture on a diskette, you just
need an PC with compatible DOS and BIOS.
To view the picture when trying to boot the disk, a VGA card is required.
If there is no VGA card present in the system or a sector read error occurs
when loading the picture, the normal "Non-System disk..." message is printed
in text mode.
The picture's fade-in effect is done with BIOS calls to change the palette
colors. Although the time of the vertical retrace of your CRT is used to do
that, on slower computers it is possible that, starting at the top of the
screen, some flickering occurs. On a 20 MHz 386 I have no problems with that,
but at 10 MHz or slower, most VGA BIOSes flicker. You can turn off the
fade-in effect with the /f option.
4. THE PICTURE
TrackPic can only use VGA (MCGA) 320x200x256 pictures in "raw" format.
Such a picture consists of a palette and the pixel data, which are stored
in two seperate files.
The palette file should have the extension ".PLT". Its length is normally
768 bytes and it consists of 256 records of R,G,B color information (0-63).
Programs like "VGA CAD" or "VGACAP" produce such a file, but with a 7-Byte
header and perhaps some chunk bytes at the end. VGACAP i.e. uses 777-byte
files. To read both types, raw and with the 7-Byte header, TrackPic loads
the file directly if it is 768 bytes long or skips the first seven bytes if
it is longer.
The picture file sould have the extension ".BLD". When using the raw data,
its length is 64000 bytes (200 rows with 320 pixels each). Again, VGACAP
and VGA CAD have a 7-Byte header which is treated in the same way as with
the palette file. The GIF picture viewer PICEM can also save this format -
it has the extension ".BAS". Picem doesn't save the palette. (WHY?)
Note: If the picture file length is < 64000, TrackPic thinks the picture is
already compressed. As an example, the DEMO.BLD file that came with this
version of TrackPic is already compressed. You can't use compressed files
yourself.
If there is interest, I could implement a GIF or PCX loader...
5. HOW TO DO IT
There are two possible ways to invoke TrackPic:
5.1. TRACKPIC <pal-file.ext> <pic-file.ext>
When giving two file names on the command line of TrackPic, the two files
will be used to read the palette (first) and picture data (second).
Example: > trackpic screen00.plt screen00.bld
would use the files "SCREEN00.PLT" and "SCREEN00.BLD".
5.2. TRACKPIC <file>
When using only one file name (without extension!), TrackPic reads the
palette file adding a ".PLT" extension to the file name and the picture
file adding a ".BLD" extension.
Example: > trackpic screen00
would, like above, use the files "SCREEN00.PLT" and "SCREEN00.BLD".
5.3. OPTIONS
5.3.1 /B - install on B: drive
Normally, Trackpic uses drive A: to install, because you normally
boot from this drive. If for any reasons you want to use B:, this
switch makes it possible.
5.3.2 /N - No user input
If this option is used, the user is at no time prompted for input:
- if there is no disk in drive A:, TrackPic aborts
- if there is a disk in A:, TrackPic directly starts
- if there occurs a read or write error, TrackPic aborts at once
5.3.3 /V - re-read picture and View
After having installed TrackPic on the disk, all used sectors and
tracks are again read and the picture will be displayed. If the
picture has errors or if it is unreadable, the disk may be faulty or
your drive doesn't support tracks >= 80.
You need a VGA card to use this option.
5.3.4 /R - no veRify
The information written to the disk are always verified to be correct.
With this switch, you can turn off this feature. But this only saves
one or two seconds and makes the whole act a little less reliable.
5.3.5 /T - Test boot sector
If you use this option, TrackPic doesn't return to DOS when ready but
reboots your machine to directly test the new boot sector.
Even if you use the /B option, your computer boots from drive A:.
5.3.6 /F - Fade-in OFF
If you don't like the effect of the picture fading in or your
computer is too slow to do this flicker-free, you can turn this
feature off with this swicth and the picture is displayed immediately.
5.3.7 /O - Override safe track limit
Normally TrackPic refuses to write pictures to disks when their
safe track limit would be exceeded. That's normally the case with
big, detailed pictures on DD disks. When you use the /O option,
the track limit will be ignored.
Be cautious! On a 360k disk, the normal maximum track is 41, whereas
a full 64k picture would require tracks 40-53. When using this option
in such an extreme case, your disk head will certainly bang against
some barrier. I had no problems with that - but be very careful!
6. EASY START
You have a picture file and want to use it as a boot picture?
Here is one way how you can do it, with just a few PD/shareware programs:
o load VGACAP
o display the file on screen in MCGA 320x200x256 mode (with PICEM,CSHOW...)
o press ALT+F4 to save the screen to disk (VGACAP function)
o quit your image viewer - there are now files SCREENxx.PLT and SCREENxx.BLD
o type "trackpic screenXX" and there you are...
recommended shareware programs:
VGACAP Copyright by Lawrence Gozum & Marvin Gozum
VGA image capture program, creates .BLD and .PLT files
PICEM Copyright by John Bridges
GIF viewer, can save picture in .BAS format (<=>.BLD)
CSHOW Copyright by Canyon State Systems and Software
viewer for multiple image file formats
PICLAB Copyright by Lee Daniel Crocker and the Stone Soup Group
best to rescale and manipulate pictures
These programs can be copied freely. Every good FTP side should carry them.
Donate the authors for their efforts if you use their programs!
7. BLAH
Although I tested this software carefully, you use it on your own risk.
I will not be responsible for any damage.
This software is copyrighted!
Private persons can use TrackPic, but for personal use only. Using the
TrackPic boot sector on a commercial disk or a freeware/fairware, etc
disk is strictly forbidden!
If you like it and your name isn't David Rasche, send me $10 or what you
think it is worth to you for my time and efforts.
If your name is David Rasche, send me a photo of Susi...
If you send $15, you'll get the latest enhanced version of TrackPic.
(Europe: $12 or DM 20)
Thomas Opheys, App. 88 Internet: iws9012@eva.fmi.uni-passau.de
Franz-Stockbauer-Weg 1
D-8390 Passau, Germany e-Mail preferred
Tel.: 0851-73971