Introduction to files for emulators

"ROM"

Recently many people use the term "ROM" to refer to dumps of cassettes, discs, cartridges and ROMs.

This term is confusing and inaccurate:

when used to describe computer/console software, because the computer may use multiple storage media,
when used to refer to entertainment software, because computer systems have games, eductational software, utilities and applications.
when used to refer to cassette/disc media, because cassettes and discs are read/write, and ROMs are Read only (see definition for ROM).

This term is accurate when used to describe software for a single use computer/console which uses a single storage media, which is ROM based, and is only used for playing entertainment software.

When asking for computer software in internet newsgroups (such as comp.sys.amstrad.8bit), to avoid confusion, please use the appropiate term.

Amstrad CPC software

The Amstrad CPC computer mainly used cassettes and floppy discs. Most disc software was sold on 3" discs because the CPC664, CPC6128 and CPC6128+ had 3" disc drives built in.

Some software, mostly application or utility based, were sold on ROM ICs. To use these, you needed a ROM board which was connected through the expansion connector on the back of the computer. The ROM IC must be plugged into a spare ROM socket. When the computer was then switched on, the software was instantly available for use.

Later the Amstrad CPC+ (CPC464+, CPC6128+) computers were released. These were mostly compatible with the Amstrad CPC so they could use the existing cassette and disc software. But these computers could also use cartridges. There was a system cartridge which contained BASIC and the Operating system, and game cartridges. When the computer was switched on (with a cartridge inserted), the software was automatically started.

The GX4000 console was based on the CPC+ design, but it can only use cartridge software.

Emulators

To run Amstrad software on a PC or Mac you need an Amstrad emulator. An emulator is a program which mimics the functions of a computer or console.

The PC or Mac are not able to use the software in it's original form (cassette, floppy disc, cartridge), so the data contained on the media must be dumped and stored in a file:

A 3" disc is dumped into a "disk image" file which have a "dsk" extension,
The sound from a cassette is converted into a "tape image" files which have a "tzx" or "cdt" extension,
A cartridge is dumped into a "cartridge image" file which have a "cpr" extension,
A ROM is dumped into a "ROM image" file.

Terms

Cassette: An Amstrad cassette is a standard audio cassette with Amstrad programs recorded onto it. A cassette is also known as a "tape".
Cartridge: An Amstrad cartridge is a plastic box containing a PCB. On the PCB is a ROM IC. The CPC+ (CPC464+ and CPC6128+) and GX4000 were the only Amstrad systems that can use cartridges.
Cartridge image: A cartridge image is a file to be used with an emulator. The cartridge image contains a dump of the data contained in the cartridge.
Disk: The 3" floppy disc has a hard plastic case, inside there is a flexible plastic disc which contains the data. The disc may be turned over, so it is possible to use both sides. A disk is also known as a "disc" and "floppy disc".
Disk Image: A disc image is a file containing a dump of a disk. Amstrad disk images normally contain the dump from a single side of a 3" disc.
Emulator: An emulator is a program which mimics (copies) the functions of a computer or console.
IC: A acronym for "Itegrated Circuit". An IC is also known as a "chip". Physically an IC is normally black in colour, rectangular or square in shape, and has many metal legs
PCB: A acronym for "Printed Circuit Board" also known as circuit board.
ROM: An acronym for "Read Only Memory".
ROM Image: A rom image is a file to be used with an emulator. The ROM image contains a dump of the data contained in the ROM
Tape: See "cassette"
Tape Image: A tape image is a file containing a dump of cassette software. This file is used with an emulator.
dump: A "dump" is a term used to describe, a file containing the data from a storage media (more commonly ROMs), and the action of obtaining the data.