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MAXIDISK.DOC
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1992-06-05
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NB: File name: MAXIDISK.DOC Revised: 1992.06.05
NB: Created by: Ulf Ronald Andersson Created: 1992.02.07
NB:
NB: File purpose: to document the release of 'Revised MaxiDisk 2.2'
NB:
NB: Copyright: Original released as PD FREEWARE by author: Max Böhm 1987.
NB: Revisions released as PD FREEWARE by author: Ulf Ronald Andersson 1992.
NB:
NB:
NB: This is not the original documentation, which seems lost to mankind.
NB: At least I have not yet found any complete archive for this utility.
NB: So I have had to take the liberty of creating this DOC file,
NB: since I have made some long-needed revisions to MaxiDisk.
NB: As follows:
NB:
NB: Revision 2.0 updates of February 1992:
NB:
NB: 1. I have implemented the XBRA protocol for all 3 vectors used.
NB: This was one of the two reasons I made this revision.
NB:
NB: 2. I have modified the memory protection method, so that MaxiDisk
NB: now is compatible with OVERSCAN.PRG and other programs that
NB: previously could crash MaxiDisk (especially when nearly full).
NB: (OVERSCAN.PRG must be started after MaxiDisk to function well)
NB: The need to use it with OverScan etc., was of course my other
NB: main reason to make this revision (by now practically rewrite).
NB:
NB: 3. I have patched the BPB handling to ensure better efficiency
NB: when using huge ramdisks, which old MaxiDisk hardly packed.
NB: BPB is still non_standard, of course, in that it has as many
NB: logical clusters as there are physical sectors, but that is
NB: how packing was made transparent to the OS.
NB:
NB: 4. I have completely rewritten the data block allocation code.
NB: The original seemed to be compiler-generated rubbish.
NB:
NB: 5. I have completely rewritten the pack/unpack routines, and have
NB: changed the packing algorithm a bit. This makes packing a bit
NB: tighter and faster, although no packing ramdisk can be FAST.
NB: At present the new MaxiDisk seems to run at one eigth the speed
NB: of QWIKDISK, as measured by QINDEX, which will do for me.
NB:
NB: 6. I have eliminated a lot of compiler-generated garbage-code, and
NB: unneeded huge file arrays (that have NEVER been used !!!).
NB: Also the insane program startup sequence, which turned the data
NB: and BSS sections upside-down. (Really...!)
NB:
NB: 7. I have also patched and streamlined each and every routine that
NB: remains in the program to get rid of that silly compiler stuff.
NB: eg: "LEA (A0),A0" and such-like ridiculous nonsense.
NB:
NB: For more technical details, read the file MAXITECH.DOC .
NB:
NB:
NB: Revision 2.1 updates of March 1992:
NB:
NB: Several routines were trimmed for higher efficiency, and one byte
NB: in the simulated 'boot' sector was adjusted.
NB:
NB:
NB: Revision 2.2 updates of May 1992:
NB:
NB: 1. The routine that searches for the MPB pointers of TOS has been
NB: improved, and now functions on all known TOS versions.
NB:
NB: 2. Some sector handling routines have been improved, though this
NB: may be masked by the delays caused by packing.
NB:
NB: 3. MaxiDisk 2.2 has been tested error-free on several TOS versions
NB: ranging from TOS 1.0 through TOS 1.4 to KAOS 1.4.2.
NB: Since no TOS-dependent features are used it should always work.
NB: Unfortunately the present release of TOS 2.6 has a bug in the
NB: code for 'warm' reset, such that no reset-proof ramdisk seems
NB: to be possible under this TOS !!! (I will investigate this)
NB:
NB:
NB: I will surely improve the program even further, but at present I
NB: think I have achieved what I set out to do. Which was to revive
NB: this great idea of a packing ramdisk, in a version acceptable by
NB: modern standards and compatible with other modern programs.
NB:
NB: The remainder of this file is the best near-original DOC's I have.
NB: Where I have discovered errors in it, or made important revisions,
NB: I have inserted notes like the one immediately below.
NB:URA: This line shows how my notes will appear below.
---------------------- Here follows older text -------------------------------
Cologne , West Germany , July 4 , 1988
---- This file is a translation of the original German README file, written
by Max Böhm, the author of this exceptional public domain program.
Translated by COLONIUS. Comments made by the translator are within
brackets.
MAXIDISK.PRG installs a resetproof ramdisk, which compresses the files
stored in it. It is usually possible, to store about 750 kB in a 500 kB
ramdisk! This version works with all versions of ROM based TOS, including
the new Blitter TOS of the MEGA STs. Any memory size, up to 4 megabyte, is
supported. (Although it makes little sense to use a ramdisk on a 512 kB
system.)
MAXIDISK.PRG should reside in the AUTO folder on your boot disk, although
you may also install the ramdisk from the desktop after booting your ST.
(In this case you should rename the program to MAXIDISK.TOS, since it is not
a GEM application and will cause trouble if started as one. It must,
however, carry the .PRG extender to autoboot from the AUTO folder.)
The first thing MAXIDISK.PRG does, is to check if there is already a
MAXIDISK installed. In this case, you are informed about the size and the
assigned partition name and the installation terminates.
After this, MAXIDISK checks for MAXIDISK.INF on drive A and B (if started
from floppy) or on the logical drive (partition) it was started from.
{Paul Varn note: If MAXIDISK.INF is not found, you are requested to enter
a size and partition letter.}
If you would rather abort the installation of the ramdisk after starting
MAXIDISK.PRG, simply hit return without entering a numeric value when
prompted to enter the desired ramdisk size. A message will inform you
that the ramdisk was not installed.
Once the MAXIDISK is installed, it is resetproof. This means that the
contents of the ramdisk will survive the reset, not the driver program
itself. You must start MAXIDISK.PRG after a reset, to be able to access the
data in the ramdisk. If you fail to do so, the ramdisk will still remain
intact over any number of "warm" resets, but it will seem to be empty (0
bytes in 0 files) until the MAXIDISK driver is reinstalled.
{Paul Varn note: Actually, you must use a re-named version of Maxidisk
called: MAXIDISK.TOS. When you do this, the screen will just blink and
return to the desktop. A symptom of a re-set fault is that when you access the
drive, the bytes are ZERO with NO FILES SHOWN. Don't worry. After running
MAXIDISK.TTP, everything will return to normal. However, it IS possible to
get such a severe system crash, that Maxidisk won't servive. This has been
rare for me. If you re-boot from the same disk or drive that Maxidisk was
started from, it will take care of itself and all will be normal without the
need to re-run Maxidisk.}
MAXIDISK.INF is an ASCII file which you may use to install the maxidisk
automatically after MAXIDISK.PRG has been invoked.
MAXIDISK.INF contains the size of the ramdisk, the drive letter which shall
be assigned to the ramdisk (C through P) and the names of programs that
should be started after the ramdisk has been installed. (You may edit this
file with any text editor or word processor that allows you to save plain
ASCII files. If you should use 1st Word (any version), be sure to switch off
the word processor mode. You may also delete MAXIDISK.INF entirely, if you
prefer to enter size and drive number manually.) The example MAXIDISK.INF
file installs a 500 kB ramdisk as drive D, copies the contents of the folder
COPY_IT to the ramdisk and finally starts SET_TIME.TOS. (see also COPY.TTP
and SET_TIME.TOS)
{Paul Varn note: Unfortunately, the person who uploaded to version of this
ARC that I found, corrupted the .INF file so that the suggested use of the
auto-run feature was not shown. I've tried several ways to do this and have
not found it. I prefere to use HEADST by CODEHEAD anyway.}
NB:URA: Better instr