【NEC】 E261 Magnetic Disk Pack Unit

In August 1966, NEC announced the E261, their first magnetic disk unit, developed for small systems. It was first shipped in March 1968.
This unit was for small computer systems using magnetic disk packs comprised of five 14-inch media, and it employed the fixed data length system based on sector marks.
It was used with small computers such as the NEAC Series 2200 Model 50, and the NEAC-3100 multi-purpose scientific computer.

E261Magnetic Disk Pack Unit Specifications
Total Memory capacity(Kchar/pack) 819
Seek time(msec) Average 200
Average rotational delay(msec) 14
Data transfer speed (Kchar/s) 83.3
Disk diameter(inch) 14
Number of disks/pack 5
Number of recording sides/pack 8
Number of tracks/recording side 64
Number of sectors/track 16
Memory capacity of 1 sector (char) 100
Recording system FM
Rotation speed(rpm) 2100

E261 Magnetic Disk Pack Unit