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The Business Master (4th Edition)
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1992-09-01
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9KB
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220 lines
_______
____|__ | (R)
--| | |-------------------
| ____|__ | Association of
| | |_| Shareware
|__| o | Professionals
-----| | |---------------------
|___|___| MEMBER
ABOUT SHAREWARE
This package contains the program named FLOPTOOL. It is
made by
Feico Nater,
Beukweg 24,
7556 DE Hengelo,
the Netherlands.
The system is available as shareware. What is shareware?
It is software which people pass around, but I, the author,
retain the rights to it. Maybe you obtained the system from a
bulletin-board and paid a few dollars for it, but I don't get
a penny of it. I expect to be paid by you, because I make my
living out of making shareware software.
Therefore, if you like this system and use it, you are
supposed to register by sending a $15-check drawn on a US-
bank. Sorry, I cannot accept credit-cards. The address:
Feico Nater Shareware, Beukweg 24, 7556 DE Hengelo, the Neth-
erlands.
Why register? Well, it costs you money. But if you do,
I will advise you about further developments. Furthermore you
will have the right to order later versions for only a few
dollars and I will be willing to listen to your wishes.
And if you don't like the system? Well, throw it away.
But you will like shareware, because it does not let you pay a
lot of money for something you dislike afterwards.
Whether you register or not, you are encouraged to pass
this system around. Give away copies to your friends. Howe-
ver, files with the extension .NAR should not be given away.
The copies you pass around must be complete and unmodified,
but file-compression is allowed. Any money you collect should
be for diskette, packing, postage only and should not exceed
five dollars.
ABOUT THE AUTHOR
I have been working with computers since 1970. I have
completed a third-level degree in computer-science. I have
been employed for many years in a big company, making defense-
equipment, and my colleagues considered me the most skilled
programmer among them. However, since the company went broke
(Gorbachev was to blame, and he did a good job) I became
unemployed and started woring as a shareware author.
The program FLOPTOOL reads anything there is on a floppy disk,
regardless whether it is a DOS-disk or not.
The results are writeen as a ASCII-file to the fixed disk.
The output file-name is FLOPTOOL.DAT.
Rather that using BIOS-functions FLOPTOOL addresses the flop-
py-controller (NEC 765) and the DMA-controller directly. This
is needed to be able to read non-DOS disks. However it does
require a computer which is absolutely compatible
Syntax: FLOPTOOL drive: /N /D /S /T:n /L:n
Drive must be A or B.
FLOPTOOL adjusts the head on every cylinder, read both sides,
finds how data is coded and writes all results to
C:FLOPTOOL.DAT.
There are two ways of recording: FM and MFM. The latter is
twice as compact. The IBM-PC uses MFM only. FLOPTOOL finds
on every track whether FM was used.
FLOPTOOL then writes onto C:FLOPTOOL.DAT:
CH=cylindernumber sidenumber, FM or MFM
Then FLOPTOOL reads the id-fields of every track. Every
sector has an id-field, which is four bytes long. With DOS-
disks these bytes are:
C: (cylinder) counted starting at 00.
H: (head, or side of the disk) on the front-side 00, on the
back-side 01.
R: (record or sector) counted starting at 01.
N: logarithm of the sectorlength, with DOS-disks always 02,
that is 512 bytes.
FLOPTOOL then writes onto C:FLOPTOOL.DAT:
CHRN=.. .. .. ..
This is followed by the complete contents of the sector.
While FLOPTOOL is reading you will see an M or an F on the
screen for every track, dependent on whether FM or MFM was
found. If a track cannot be read, no letter appears.
The following switches can be given when FLOPTOOL is started:
/N read id-fields (CHRN) only, not the contents of the sec-
tors.
/D read even cylinders only, skip odd cylinders.
/S read sectors one by one. Sometimes this produces exacter
results. When this switch is not given FLOPTOOL will read
each track at once.
/T:n start at cylinder n (hexadecimal)
/L:n all sectors have length n. Use this coding: 00=128,
01=256, 02=512, etc.
The switches /S and /L are useless when /N is given.
Further details.
When showing the contents of the sectors FLOPTOOL suppresses
lines which are equal.
Floppy disks from another computer kan be very different. The
cylinders, heads, sectors may have different numbers. The
IBM-PC will refuse to read such a disk, FLOPTOOL will do.
The last byte of the id-field is supposed to contain the
length of the sector. This value may be wrong, and then it is
hard to find out how long the sector really is. So it is
possible that FLOPTOOL reads too many or too few bytes. If too
few bytes are read, the rest of the sector remains unread. If
too many bytes are read then FLOPTOOL reads the gap between
the sectors and possibly fractions of the following sectors.
This may cause synchronisation-problems, so that the bytes
seem damaged.
The /L switch may solve the problem. When this switch is
given, FLOPTOOL will ignore the last byte of the id-veld and
uses the value from the switch in stead.
With 5 1/4 inch disks some more problems are conceivable,
because these disks may have 40 or 80 cylinders.
"True" 40-cylinder disk in 80-cylinder drive:
A "true" 40-cylinder disk is a 40-cylinder disk which has been
formatted and written in a 40-cylinder drive.
FLOPTOOL will read the even cylinders easily.
On the odd cylinders FLOPTOOL will sometimes read one, someti-
mes the other neighbouring track.
"False" 40-cylinder disk in 80-cylinder drive:
A "false" 40-cylinder disk is a 40-cylinder schijf which has
been formatted and written in a 80-cylinder drive.
FLOPTOOL will find the odd cylinders unreadable, unless the
disk has been used before.
80-cylinder disk in 40-cylinder drive:
The odd cylinders are out of reach, and the even cylinders may
be hard to read.
"False" 40-cylinder disk in 40-cylinder drive:
This disk may also be hard to read, particularly if it has
been used before.
When reading a 40-cylinder disk in a 80-cylinder drive you
will find the /D switch convenient.
The floppy-controller in the IBM-PC is usually a NEC uPD765A.
As far as I know a 7265 is never used. The data-pattern is
this:
MFM-mode FM-mode
GAP: 80 x 4E 40 x FF
SYNC: 12 x 00 6 x 00 765 only
IAM: C2 C2 C2 FC FC 765 only
GAP: 50 x 4E 26 x FF 765 only
for every sector:
SYNC: 12 x 00 6 x 00
IDAM: A1 A1 A1 FE FE
C H R N: C H R N C H R N
CRC: checksum checksum
GAP: 22 x 4E 11 x FF
SYNC: 12 x 00 6 x 00
DATA AM: A1 A1 A1 FB FB (of F8)
(or A1 A1 A1 F8)
DATA: data data
CRC: checksum checksum
GAP: