Editing Amstrad CPC (section)

===Floppy disk drive===
[[File:Schneider CPC6128 Diskettenlaufwerk.jpg|thumb|Built-in disk drive of the CPC 6128]]
[[File:CPC6128 loading Turbo Esprit from floppy disk.flac|thumb|A CPC 6128 loading ''[[Turbo Esprit]]'' from its internal floppy drive]]
[[File:3 inch floppy disks.jpg|right|thumbnail|3-inch floppy disks used on CPC machines]]
Amstrad uses [[Panasonic|Matsushita's]] 3" floppy disk drive [ref: CPCWiki], which was compatible with [[Hitachi]]'s existing [[Compact Floppy|3" floppy disk format]].<ref name="pountain198501" /> The chosen drive (built-in for later models) is a single-sided 40-track unit that requires the user to remove and flip the disk to access the other side.<ref name="6128 Tech spec"/> Each side has its own independent write-protect switch.<ref name="6128 Tech spec"/> The sides are termed "A" and "B", with each one commonly formatted to 180&nbsp;KB (in [[AMSDOS]] format, comprising 2&nbsp;KB directory and 178&nbsp;KB storage) for a total of 360&nbsp;KB per disk.

The interface with the drives is an NEC 765 [[Floppy disk controller|FDC]], used for the same purpose in the IBM [[IBM Personal Computer XT|PC/XT]], [[PC/AT]] and [[IBM Personal System/2|PS/2]] machines. Its features are not fully used in order to cut costs, namely [[Direct memory access|DMA]] transfers and support for [[single density]] disks; they were formatted as [[double density]] using [[modified frequency modulation]].

Discs were shipped in a paper sleeve or a hard plastic case resembling a [[compact disc]] "jewel" case. The casing is thicker and more rigid than that of 3.5&nbsp;inch diskettes, and designed to be mailed without any additional packaging{{Citation needed|date=December 2010}}. A sliding metal cover to protect the media surface is internal to the casing and latched, unlike the simple external sliding cover of Sony's version. They were significantly more expensive than both 5.25&nbsp;inch and 3.5&nbsp;inch alternatives. This, combined with their low nominal capacities and their essentially proprietary nature, led to the format being discontinued shortly after the CPC itself was discontinued.

Apart from Amstrad's other 3-inch machines (the [[Amstrad PCW|PCW]] and the [[ZX Spectrum|ZX Spectrum +3]]), the few other computer systems to use them included the [[Sega]] SF-7000 and CP/M systems such as the [[Tatung Einstein]] and [[Osborne Computer Corporation|Osborne]] machines. They also found use on embedded systems.

The [[Shugart bus|Shugart]]-standard interface means that Amstrad CPC machines are able to use standard 3", 3½" or 5¼" drives as their second drive. Programs such as ROMDOS and ParaDOS extend the standard AMSDOS system to provide support for double-sided, 80-track formats, enabling up to 800&nbsp;KB to be stored on a single disk.

The 3-inch disks themselves are usually known as "discs" on the CPC, following the spelling on the machine's plastic casing and conventional [[British English spelling]].