FORMAT [#channel,] medium



Each medium where data can be stored as files (disks, ramdisks, microdrives or hard disks) has to be given a structure which is recognisable by QDOS. This is done by FORMATting it. Each medium can also be given a name of up to ten characters long. The command FORMAT clears a medium from scratch so that any data stored there is definitively lost. Be careful!

The following standard devices can be formatted:

  • MDV1_ .. MDV8_ - microdrive cartridges

  • FLP1_ .. FLP8_ - floppy disks

  • RAM1_ .. RAM8_ - ramdisks

  • WIN1_ .. WIN8_ - hard disks

Depending on the type of medium, several additions to the pure medium name are possible:

MDV Up to ten characters can be added, these will form the name of the cartridge, eg:


FLP As with microdrive cartridges, a medium name can be added. If the eleventh character of the name is an asterisk (*), the disk will be formatted single sided, ie. just the first side is used. In order to use the single sided only option, is it necessary to put the whole parameter in quotes, eg:

FORMAT "flp1_TEST *"

This is not applicable to HD and ED disks: their density will also be affected, making them single sided double density (SSDD). If a single sided disk can still be bought today, it will actually be a double sided disk of low quality.

With Super Gold Card, Gold Card and SMS, an appended asterisk plus a letter which indicates the density will format the disk accordingly: S, D, H and E are allowed, eg:

FORMAT "flp1_TEST*h"


RAM This depends very much on the ramdisk drivers:

With standard static ramdisks, which are built into most disk interfaces and available as public domain, you need to specify how many sectors are to be allocated to the ramdisk by adding the number of sectors to the device name, eg:

FORMAT ram1_200

formats ram2_ to 200 sectors (100K).

These static ramdisks must be FORMATted before use.

On the other hand, the Qjump ramprt ramdisk (provided with Qpac 2 and various expansion boards, including Trump Card, Gold Card and Super Gold Card) is dynamic - it adapts its size automatically to the size of the files being stored on it - there is no need to FORMAT the ramdisk prior to use. This can however also be used as a static ramdisk.

Trump Card, Super Gold Card and Gold Card ROMs also contain a special variant of a ramdisk which allows you to produce an image of a microdrive cartridge on a ramdisk, for example by using:

FORMAT ram4_mdv2.

Faulty files are marked with an asterisk added to the end of their filenames. Although this may allow you to ‘rescue’ a corrupt microdrive cartridge those files marked with an asterisk are faulty and therefore unreliable.

The name of a ramdisk is always the name of the medium without an underscore, eg. RAM1 for RAM1_; this is the same on dynamic ramdisks.

WIN A medium name can normally be stated, as with a microdrive cartridge. Please check the documentation of the hard disk drivers, they differ very much! For example, the firmware on the Falkenberg interface disables FORMAT for hard disks until certain settings have been specified with another command.

On the THOR, an asterisk needs to be included, eg:


See below.

SMS for ATARI computers and QXL / QPC, expects you to have already partitioned the hard disk using the computer’s native commands. On ATARIs, under SMSQ/E you then need to identify the drive and partition using WIN_DRIVE. After that, you can use the normal QL FORMAT command on all these systems, however, SMSQ/E has adopted a level of protection which insists that you must use the WIN_FORMAT command before FORMAT and the FORMAT command itself will display two characters on screen and ask you to type them in.

You should then use WIN_FORMAT to protect the partition again.

The standard drivers for the ST/QL Emulators adopt a form of protection in that you will need to type in the two characters shown on screen as with SMSQ/E.

You can also only FORMAT a hard disk from SuperBasic Job 0 and then only when Channel #0 is OPEN.

If the hard disk has already been partitioned by the Atari ST (the first partition will normally be marked GEM or BGM), then you will be asked to enter the number of the first partition to be used by QDOS and the number of subsequent partitions ot be used for this disk.

Under SMSQ/E on the QXL or QPC, this same two- level protection is adopted. However, instead of passing the medium name of the hard-disk, you have to pass the size of the QL hard disk to be created in megabytes, for example:


This will create a 20 Megabyte hard disk on PC drive C:

On early versions, the maximum size that could be created was 23 Megabytes and only one drive could be created. Later versions allow you to create WIN1 to WIN8 (all on drive C:).

After formatting, FORMAT will either report that the process has failed (error -14), because there was no cartridge/disk in the drive or if the medium was faulty.

The command will also fail if the given device was write-protected.

If everything was okay, a small message is printed to the specified channel (default #1) indicating how many sectors could be achieved and how many were good. If the two numbers differ, QDOS will have marked some sectors as bad and will ignore them. However, experience shows that if the difference between the two numbers is great, it can be very dangerous to store important data on those disks/cartridges.

It is recommended that new microdrive cartridges should be formatted 10 times before use (you should expect to get about 220 available sectors). It may also be useful to try formatting the cartridge in the other microdrive.


FORMAT mdv2_Startup

formats cartridge in microdrive 2

FORMAT "mdv2_Startup"

as above.

FORMAT flp1_backup

formats disk in disk drive 1

FORMAT "flp1_backup *"

as above but single sided

FORMAT "flp1_backup*d"

double sided, double density

FORMAT "flp2_backup*h"

double sided, high density

FORMAT ram1_100

format ramdisk 1 to 50K

FORMAT ram1_

remove ramdisk 1

FORMAT ram1_mdv1

format ram1_ to 255 sectors and copy cartridge in microdrive 1

Notes on the different media:

The traditional microdrive is relatively slow and unreliable, and cartridges need to be formatted several times to give good results (usually around 210-220 sectors) - pushing them firmly into the microdrive slot while they are being formatted is said to be more efficient.

However, as new cartridges are becoming more rare and expensive today, the next best and very highly recommended upgrade are disk drives.

It is also becoming less and less common to find users who can read information stored on microdrive, SMS and emulators for example, do not support microdrives.

3.5” double density disks (720K)

These are pretty cheap and you can get them everywhere (although the quality does vary); they have become a standard on the QL, although it is becoming ever more difficult to find replacement disk drives. FORMAT should report 1440 sectors.

3.5” high density disks (1.4Mb)

These are also fairly cheap and you can get them everywhere (although the quality does vary). These have become the new standard disks used by IBM compatible computers and therefore the disk drives are easy to obtain. FORMAT should report 2880 sectors.

3.5” extra density disks (3.2Mb)

These are fairly expensive and difficult to obtain as they were never really accepted in the IBM PC world, although for a time, they looked like becoming a new standard for the QL, being very quick and storing a lot of information. FORMAT should report either 1600 or 6400 sectors (see note 8).

5.25” disks (720K)

These are also widely spread in the QL scene, especially in the USA, although they are now becoming less and less common. With the introduction of the Super Gold Card and Gold Card by Miracle Systems Ltd, high density (HD, 1440K) and even extra density (ED, 3200K) drives have become available to QDOS for the first time. These formats are several times faster and even more reliable, not to mention the increased space for programs and data.

Hard disks

These are becoming more and more common, with them being readily available to people using Emulators on other computers, and also now the release of relatively cheap interfaces and disk drives for the QL and AURORA.


These are not specific to any hardware configuration because they only exist in RAM and any stored data is lost if the machine is reset or turned off. On the other hand, ramdisks are extremely fast.


Unless you have a Minerva ROM (see below), do not try to FORMAT a microdrive whilst any microdrive is still running, since this will report an ‘in use’ error.


will be zero if no microdrives are running.


On the THOR XVI (v6.37 and earlier), there existed a bug when accessing anything greater than win2_.


If there is no disk in a drive, FORMAT may also fail with a read only error (-20) instead of reporting not found (-7).


You cannot use FORMAT n1_flp1_ (for example) to FORMAT a medium over the network.


The ST/QL drivers cannot FORMAT the fifth and subsequent partitions on the hard disk unless the extended partition table is in the form used by SUPRA, ICD and similar drives.


Minerva (pre v1.98) had some bugs in the code for FORMATting microdrives.


FORMAT expects the specified channel (or #1) to be OPEN, otherwise an error will be reported.


FORMAT cannot report a number of sectors in excess of 32768 and so may return wrong values on large capacity drives. SMS correctly reports the number of sectors obtained, although on an ED disk, FORMAT will report 1600 Sectors (DIR will show the figure of 6400 sectors instead!). This is because on an ED disk, sectors are 2048 bytes long instead of the usual 512 bytes expected by the QL device drivers (which have to be fooled to see each sector as 4x512 byte sectors).


On Minerva v1.78 (and later), a check is carried out before performing FORMAT to see if there are any files open on the desired medium. This stops Digital Precision’s Conqueror and Solution from working correctly. To switch it off, use:

POKE !124 !49, PEEK (!124 !49) || 128


As with Minerva, you cannot FORMAT a medium if there are any files open on that medium (‘Is In Use’ error is reported). If there is a problem during the FORMAT process, SMS will emit a series of BEEPs. However, be warned that an error message is not always displayed and the FORMAT may appear to have completed correctly!! SMS does not allow you to access the QL’s microdrives, nor can it solve the problem on the QXL below. SMS can corrupt floppy disks (so they have to be thrown away) if you try to FORMAT them to the wrong density.

Some users have reported problems in using SMS to FORMAT Double Density disks in ED disk drives linked to a Super Gold Card. This appears to afflict versions of SMS after v2.85 and all makes of ED drives. The problem only occurs if you specify the density with FORMAT ‘flp1_NAME*D’ or FLP_DENSITY ‘D’. In these cases, a noise is emitted during FORMAT to indicate that it has failed, but SMS still reports 1440/1440 sectors, even though subsequent attempts to access the disk report ‘Not Found’. The answer is to not use FLP_DENSITY in this instance.


You cannot reliably FORMAT floppy disks from scratch on most PCs using this emulator. FORMAT merely re-formats an already formatted disk. Prior to v2.67 of SMS there existed several further problems with FORMAT on QXL.


The THOR XVI, v6.37 (and later) allows a variant of the medium name to deal with the THOR’s hard disk:

FORMAT "win1_options*name"

The available options which can be specified are:

  • /C : Certify drive before formatting - this reconstructs the THOR’s defect list, describing the bad sectors and tracks;

  • /Q : Quick reformat - merely sets up new directory map;

  • /F : Fast reformat - does not verify the disk;

  • /Gn : Set group or cluster size in blocks. Default = /G16;

  • /Dn : Set directory size in number of groups or clusters. Default = /D2.


FORMAT 'win1_/Q*Main'
FORMAT 'win1_/G16/D2*THORDisk'


Prior to v2.71 of SMS FORMAT flp3_1 on the QXL could in fact FORMAT WIN1_.


Before formatting, the number of tracks on a disk can be specified with FLP_TRACK. HD and ED disks can be formatted to different densities if FLP_DENSITY was used to override automatic detection of the density. See WIN_FORMAT for hard disk protection. The DMEDIUM_XXX functions, starting at DMEDIUM_DENSITY return various details about how a medium has been formatted.