The FACOM 601 was Fujitsu's first magnetic tape unit for computers employing a tension arm shock absorber mechanism. It was completed in August 1960.
The FACOM 601 employed a tape drive system where the tape was fed by pressing it against a continuously rotating capstan with a pinch roller. There were two capstans, one each for forward and reverse feed, which rotated in directions opposite each other. A tension arm shock absorber mechanism was used because the reel could not respond to sudden movements when starting or stopping the tape. Recording density of the unit was a low 133bpi (bits per inch), but Fujitsu later developed the FACOM 602 which increased this recording density to 333bpi, and also allowed reading of tapes written with the FACOM 601. With this tape drive system, it was impossible to prevent shock to the tape during starting and stopping, but reliability was ensured by using sandwich tape. However, recording resolution was poor, and it was extremely difficult to improve recording density.
| FACOM 601L | FACOM 602 | |
|---|---|---|
| Completion date | August 1960 | About 1962 |
| Tape speed | 75inch/s | |
| Data transfer speed | 10,000 digits/s | 25,000/10,000 digits/s |
| Recording density(bpi) | 133 | 333/133 |
| Recording system | NRZI | |
| Head | 7-track write/read 2-gap head | |
| Tape used | Sandwich type 3M tape #486 | |
| Tape drive system | Capstan and pinch roller system (Tension arm shock absorber mechanism) |
|
| Rewind time | 6.5 min | |
| 2-channel cross call | Not possible | |
| Main connected systems | FACOM 222, 231 | FACOM 222, 231, 241 |
