home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Acorn User 4
/
AUCD4.iso
/
utils
/
enhancers
/
formatplus
/
Format+Doc
next >
Wrap
Text File
|
1998-08-08
|
6KB
|
188 lines
FormatPlus 1.03
==========
A small module containing extra format types, all available via the *Format
command and a useful subset available via the ADFS Filer.
While this largely duplicates the functionality of !AFormat and !FDFormat, it
is not intended as a replacement; these two applications are better if you
want any format which isn't in the ADFS Filer subset (those which are are
listed below). However, for command line, it fully replaces AFormat and
FDFormat.
(Note: the ADFS Filer won't correctly identify the size of non-standard
disks, though it does at least tell you if it's ADFS or DOS format. This
appears to be outside my control, by 'legal' means at least.)
The available formats
---------------------
Only the predefined disk shapes are available from the ADFS Filer's format
submenus.
* ADFS
The format name has the form
ATnSnZmLm
where:
A indicates that this is an ADFS format
T number of tracks per side (4 to 82)
S number of sectors per track (5 to 21, see the density table)
Z sector size (L or S, representing 1K or ½K)
L LFAU size (L or S, representing 128 bytes or 64 bytes)
Defaults are available for the sector size and the LFAU size.
For the sector size, see the density table below: where only one sector size
is shown for a given number of sectors, that is the default; where two are
shown, you must specify which.
The LFAU size, if not specified, is determined by the density: for high
density, the smaller size is used, and for double and double+ densities, the
larger size is used. This is in line with the standard ADFS formats. (The
minimum allocatable unit is 16 times the LFAU size.)
The following disk shapes are predefined:
Name Size tps spt Density
---- ---- --- --- -------
EX 820K 82 5 Double
E+ 960K 80 6 Double+
E+X 984K 82 6 Double+
FX 1804K 82 11 High
tps = tracks per side sector size = 1K
spt = sectors per track LFAU = default
Examples:
Format 0 AT82S21 Large
double sided, high density, 82tps, 21 512-byte spt,
64-byte LFAU; 1722K on disk, 1708K free
Format 0 A Urk
(as shown in table); 1790K free
Format 0 at80s11LL
ds/hd, 80tps, 11 1K spt, 128-byte LFAU
1760K on disk, 1746K free
* DOS
The format name has the form
ATnSnCmRnHn
where:
A indicates that this is an ADFS format
T number of tracks per side (4 to 82)
S number of sectors per track (5 to 21, see the density table)
C cluster size (L or S, representing 1K or ½K)
R number of entries in the root directory
H number of sides (1 or 2)
The sector size is fixed at ½K; the density is determined by the number of
sectors (see below).
Defaults are available for the cluster size, the number of root dir entries,
and the number of sides.
The cluster size (roughly equivalent to the minimum allocatable unit) always
defaults to the smaller size.
The number of entries in the root directory defaults to 112, unless the
capacity of the given format is 1MB or more, in which case the default is 224
(unless the large cluster size is used, in which case it's 240). So you'll
always get 112 entries for double and double+ densities.
The number of sides defaults to 2 (double sided).
The following disk shapes are predefined:
Name Size tps spt Density
---- ---- --- --- -------
DOS/MX 820K 82 10 Double
DOS/M+ 960K 80 12 Double+
DOS/M+X 984K 82 12 Double+
DOS/QX 1722K 82 21 High
tps = tracks per side sides = 2
spt = sectors per track cluster size = small
Examples:
Format 0 AT80S21 Large
double sided, high density, 80tps, 21 512-byte spt,
64-byte LFAU; 1680K on disk, 1662½K free
Format 0 DOS/QX Urk
(as shown in table); 1704½K free
Density selection
-----------------
The number of sectors (-s) and the sector size (-k) together determine the
density:
| Number of sectors
| 5 6 10 11 12 20 21 D = double density
---+--------------------------- D+ = double+ density
Sector ½K | * * D D+ D+ H H H = high density
size 1K | D D+ H H * * * * = invalid
Density availability
--------------------
Dbl Dbl+ High
Arc, pre A5000 € × ×
A5000 and later € ? €
Risc PC & A7000 € € €
The LFAU
--------
This is really beyond the scope of this help text; however, the following
description should help:
The larger the LFAU size, the smaller the space needed by the disk map - at
the expense of some potentially wasted space - whether it's actually wasted
or not depends on the sizes of the files you store on the disk. Full details
are beyond the scope of this help text; more information may be found in the
PRMs.
Selecting a format with ½K sectors can create wasted space; conversely, given
a suitable mix of file sizes, you may find you have a little spare space you
wouldn't have had with the equivalent 1K sector size format.
Correspondences with standard formats
-------------------------------------
Some format names correspond to formats supplied by ADFS (well, FileCore) and
DOSFS, for example AT80S10ZL = F, and DT80S9 = DOS/M. It's probably better
that you use the 'standard' format names for these ;-)
Disclaimer
==========
Disks formatted using FormatPlus's PC formats may not be readable on other
computer systems. In particular, to read them on PCs may require the use of a
TSR such as FDREAD (don't assume that just because ScanDisk verifies it...).
Other systems may crash or simply not recognise the disk format.
DOSFS appears to cope well, though.
Contact
=======
Darren Salt
ds@youmustbejoking.demon.co.uk