PCW Disc Types
How to use Disckit
The Disc Verify, Format & Copy Program
This program, supplied as standard with all PCW's on the CP/M utilities disc, is a very useful tool
not only for formatting
discs but also verifying that discs are fully readable - very important
these days with so many poor quality discs in circulation, not to
mention the fallibilities of the disc drives themselves.
broadly comparable to the similar facilities built into LocoScript 2, 3 and 4 but
it gives more useful details about disc problems (notably the names of the files
suffering from errors) and is normally far quicker
& easier to use for disc copying.
Users of the 8256/8512/9256/10 still using the originally supplied version of LocoScript 1 will have come across Disckit before
because it is the only way of formatting discs. However, 9512
users who have been brought up from the outset on Loco 2 (which supports disc formatting, copying and verifying on the f2 Disc menu), are often unaware of it.
The crowning advantage
of Disckit for 9512 users and others with high density drives is that copying a disc is a much less tedious task because a full 720k disc can be copied in just two parts rather than ten or more under LocoScript. This is because less of the computer's RAM memory is occupied by the program itself so more of the RAM is available for holding the disc information being copied ... so it can do it in fewer parts (disc swaps).
For those with two disc drives (an A and a B), Disckit has the facility to read from a disc in one drive and write to a disc in the other. This means that copying can be done in one go without disc swapping. Moreover, for those with both 3" and 3.5"
drives, this means that you can take a back up copy of valuable data from
one drive to the other (eg from the more fallible 3" discs to the more secure 3.5"
species) but, as with LocoScript, not all add-on drive combinations are
Disckit is designed
to prevent incomplete / unsuccessful target discs from being used, whether from
a fresh format or a copy. It does this (a) by offering only Cancel or Re-try as
options when an error is found during formatting or copying (whereas when
verifying, Ignore is also an option) and (b) by removing the format info in
track 0 at the outset and only reinstating it upon successful conclusion. Hence,
hitting C to Cancel during the format / copy results in an unusable disc
("disc not formatted, format not recognised" etc). Best plan is
therefore to Verify all discs involved before embarking on a copy or re-format
. . . . . & Disc Types
copying or verifying discs using Disckit,
ALWAYS write protect the disc you are copying
FROM or that you are verifying .... just in case you make a mistake when
swapping discs or hit Format instead of Verify!
The design of 3" disc write protect tabs varies by brand so may be a slider at the rear of the top surface or a lever within the leading edge of the disc. Whichever, if the write protect hole is open (so that you can see right through the round hole), it's protected; if you can see a red or white disc it is NOT.
On 3.5" 720k double density discs, write protecting is always by means of a slider tab (over a rectangular hole) on the under side of the disc - again an open hole = protected, blocked = NOT. High Density 1.44mb 3.5" discs, which can be used on a
9256/9512+/PCW10 without adaptation, have a second rectangular hole in them (to denote they are HD discs) without a tab and must not be confused with the write protect hole.
NB. Many manufacturer's original
program discs are intentionally made without write protect tab sliders or levers - to stop accidental over-writing -
so this does not signify that the disc is damaged.
3.5" discs only fit into the drive one way up but 3" CF2's will fit either
way because the same physical discs are designed to suit all PCW's.
Care must be taken as they may be used in two different ways:
180k format - PCW 8256 & 8512's 'A' drives - have just one read/write head so you have to turn the
disc over to access the other side. By convention, these are
called the 'A' and 'B' sides and each can hold 173k of data after
720k format - the drives fitted to the 8512 as drive 'B' &
all 9512 drives not only pack double the data into the same space but also read
BOTH sides at once so the capacity is four times as much - 720k (706k for data after formatting). Once a
3" disc has been formatted as double density,
the whole of the disc has been used so DO NOT turn it over in the hope of another 720k on the other side!
If you do, you'll wipe the lot so
make a habit of using the side marked 'A' uppermost (9512)/to the left
(8512) and mark the spine label accordingly.
Some early manuals recommended
using only of 'CF2DD' discs for the 720k Double Density format. Don't
worry - any decent CF2 should be able to be DD formatted.
Beware relying on
sub-standard discs! When the leading disc manufacturers ceased
production of CF2's, a mass of horrid discs were imported from
southern Europe and sold under a variety of names, including
(wrongly) Amsoft. These are prone to sudden and complete failure and
can be recognised by having criss-cross hatchings on the disc case
and white write protect levers in the leading edge of the disc (white
showing through the two smaller holes when the disc is laid flat).
Maxell discs are plain surfaced (no hatching) with red levers whilst
proper Amsoft ones are hatched but write protection is by a white
slider tab on the rear left of the upper surface of the disc (so when
laid flat, there's a hole showing white on the right but a
rectangular slider tab on the left).
To Start Disckit
Switch on your PCW and insert your CP/M utilities disc (or preferably a copy of it)
into drive 'A'
As soon as the initial "lines going down the screen" display switches to the CP/M start-up screen, hit the STOP key a couple of times. This aborts any automatic copying of files from drive A to M which is
not only unnecessary for Disckit but also reduces the amount of RAM available for storing disc images when copying.
At the ensuing
A> prompt, type in DISCKIT then hit the Enter key. Note the spelling but it may be entered in either upper or lower case (as with all CP/M commands).
When prompted to do so, remove the CP/M disc from Drive A
The main menu screen appears with a representation of the f1/3/5 function and Exit keys
Once in Disckit, all commands are by single keystroke ie no "Enter" is required
to confirm an action.
following descriptions relate to the most common program version
(1.2 - as shown on the initial screen display). Earlier versions
are similar in operation but the screen prompts are less "user
To Verify a Disc
Hit the f1 key.
On two drive m/cs, an extra menu appears asking for the drive letter so hit f1 or f3 as appropriate. This display is geared to look like an 8512 so the upper of the function keys, f3, is used to signify the upper drive (A:) and the lower, f1, the lower drive (B:) so is a bit confusing on a twin drive 9512 where they are side by side! On an 8512, if you are not sure whether the disc is single or double density, choose drive B as this can read both single and double
whereas the A can only read singles so will report a double as 'not formatted'.
A screen appears asking you to confirm that this is what you want to do. Insert the disc and respond with Y as prompted.
The display will show progress by an incrementing track number - there are 40 tracks on a single density disc
('CF2 format' - 0 to 39) and 160 on a double density disc ('CF2DD' -
0 to 159).
If problems do arise, the track number, sector number and name of the file involved will appear followed by the entreat to Retry, Ignore or Cancel. Initially try hitting R to re-try in case the problem can be overcome by a further 10 attempts to re-read, during which the disc drive will emit the characteristic "eee-awe" ("donkeying") sound as the head retracts and re-positions in an attempt to re-read the affected sector. If failure still results on the same sector, note the track, sector and file name then hit I to ignore and continue then, upon completion, try the disc in a different drive (if possible) to determine whether the problem is with the disc or the drive
alignment/slipping belt. On really hopeless cases, hit C to cancel the verification and return to the main menu.
If a CF2 format disc verifies fine until track 8 then fails on every
sector, this is a sign that it has been reformatted as double (CF2DD)
with the other side uppermost .... so try it that way up in a DD
drive. For technical reasons, the later DD formatting does not quite
obliterate the original CF2 format. The original directory is left
intact thereby giving the misleading impression (eg in LocoScript)
that the disc is a valid CF2 and the data is retrievable. This is not
so unless a complete file resides totally within the first half dozen
To Format a Disc
Hit the f3 key
The prompts and action from hereon are the same as for verifying above except that, when a disc problem arises, the only options proffered are Retry and Cancel. Note that if you do Cancel a format, the disc will not be useable because the system and directory tracks (0 and 1) are only written at the end of the process if the rest has been successful.
When you first insert a freshly formatted
disc into LocoScript, the Disc Manager screen will report the drive
as having 173 or 706k free, but there will be NO columns for it in
the lower (files) part of the screen. Don't panic! With no
files on the disc there's nothing to display .... so LocoScript omits
the file columns and the cursor
left/right keys have no effect. The trick is to use the
SHIFT+Cursor keys to move the upper Group cursor (highlight). A good
way of initialising a new disc is to select TEMPLATE.STD on drive M,
select Copy file (f3 in Loco1 or f3 menu in Loco2/3/4) then hit SHIFT+Cursor Left until
the highlight reaches Group 0 of the new disc then hit Enter twice.
Once the file has been copied, the disc manager screen will refresh
and a column for this group will magically appear!
For more info
on the first use of newly formatted discs in LocoScript and how the
Disc Manager Screen's cursors operate, see our PCW
Help & Tips page
To Copy a Disc
A wise precaution here, especially on 3" discs, is to verify the 'source' disc ('disc to Read') and to format the 'destination' or 'target' disc ('disc to Write') before undertaking the copy so as to prove that both discs are fully OK (or that any problems on the source are confined to an unused area ("fortunately this does not matter" report).
protected the source disc, place it on the left hand side of the top of your PCW and the destination
disc on the right (so that you are working naturally left to right
and feed the discs in the correct sequence).
Hit the f5 key
On single drive machines, where you can only read from a disc in A and write to a disc in A, simply insert the source disc and respond Y to the "Are you sure?" prompt.
On twin drive machines, select the drive of the source disc (with f1/f3 as described under Verify) then choose the destination (again with f1/f3). Note that on an 8512 you can copy a 180k format disc by placing the source in B and the target in A, but not vice versa as 720k discs cannot be read in a single density drive. Insert the discs, re-check that they're the right way around then hit "Y".
When reading from and writing to the same drive, respond to the "Load disc" prompts as
necessary (switch discs then hit a key). 180k discs will copy in one hit, 720's will take two (tracks 0 to 79 first time then 80 to 159) except on a 9256 when it will need four swaps.
a wise move is now to Verify the destination disc.
To Quit the program
the main menu, hit the Exit key to return to the CP/M A>
you have now finished with the PCW for this session, just switch
off. If you now want to start up LocoScript, hit Shift+Extra+Exit
altogether to re-start the PCW then insert your Loco Start of Day
Disc (SOD disc).
for our PCW
Disc Conversion page
here for the PCW Help & Tips page
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This page last amended 2nd January 2015
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