DECtape (originally called
Microtape) was a
magnetic tape data storage medium used with many
Digital Equipment Corporation computers, including the
PDP-6,
PDP-8,
LINC-8, PDP-9,
PDP-10,
PDP-11,
PDP-12, and the
PDP-15. On DEC's 32-bit systems,
VAX/VMS support for it was implemented but did not become an official part of the product lineup. DECtapes were 3/4 inch wide, and formatted into blocks of data that could each be read or written individually. Each tape stored 184K
12-bit PDP-8 words or 144K
18-bit words.
Block size was 128 12-bit words (for the 12-bit machines), or 256 18-bit words for the other machines (16, 18, 32, or 36 bit systems). From a programming point of view, DECtape behaved like a very slow disk drive.