See here for more details: [http://cpc.sylvestre.org/technique/technique_catart1.html All about CAT'arts (FR)]
==== CP/M terminology ====
Record: The basic unit of data access in CP/M, 128 bytes in size. This was the standard size for transferring data between memory and disk.
Bloc: A group of records, 1 KB in size. Blocs were used to improve disk access efficiency by reading/writing multiple records at once.
Extent: A group of blocs, 16 KB in size. CP/M used extents to manage file allocation, with each extent corresponding to a portion of a file on disk.
Sector: The smallest physically addressable unit on a disk, 512 bytes in size on Amstrad CPC. CP/M accessed the disk at the sector level, though users typically worked with records.
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