|
IBM 2401 Magnetic
Tape Unit
- Models 1 - 3 announced April 7, 1964 and withdrawn
July 16, 1979
- Models 4 - 6 announced August 9, 1965 and withdrawn
July 16, 1979
- Model 8 announced November 5, 1970 and withdrawn
July 16, 1979
- All models and features withdrawn March 9, 1981
Models 1, 2 and 3
Each of these models, specifically designed for use
on the IBM System/360, used a nine-track read/write
head and had a single density of 800 bytes per inch.
Any of these models could be attached to IBM System/360
through the 2803 or 2804 Tape Control.
- Up to eight 2401s, Model 1, 2 or 3, could be attached
to a 2803 or 2804 Tape Control.
- The 2401 could read magnetic tape in a read-backward
mode.
- The 2401 had a nominal inter-record gap of .6 inches.
- By use of a special feature, the 2401 could read
or write seven-track magnetic tape, providing compatibility
with 727, 729 and 7330 magnetic tape units with densities
of 200/556/800 bpi.
- For nine-track operations, the 2401 had correction
of one or more errors in a single track on a reread
operation.
- By use of IBM 2816 switching units, Model 1 and
special features, up to 16 tape drives could be switched
on up to four channels.
- The IBM 2401, Models 1, 2 and 3, had the following
performance ranges:
| |
Model
1 |
Model
2 |
Model
3 |
| Data
rate (8 bit bytes per second) |
30KB/
60KD |
60KB/
120KD |
90KB/
180KD |
| Tape
Speed (inches per second) |
37.5
|
75.0 |
112.5 |
| Nominal
IRG Time (milliseconds) |
16.0 |
8.0 |
5.3 |
| Rewind
Time (minutes) |
3.0 |
1.4 |
1.0 |
| Rewind
and Unload (minutes) |
2.2
|
1.5 |
1.1 |
|
Models 4, 5 and 6
Also specifically designed for use on the IBM System/360,
these models of the 2401 used a nine-track read/write
head and recorded data at 1600 bytes per inch. They
could be attached to IBM System/360 through the IBM
2803/2804 Tape Control, Model 2.
- Up to eight 2401, Models 4, 5 or 6, could be attached
to the 2803/2804 Tape Control, Model 2.
- The 2401 could read magnetic tape in a read-backward
mode.
- The 2401 had a nominal inter-record gap (IRG) of
.6 inches
- A dual density special feature gave the 2401 the
capability of handling the nine-track tapes of all
models in the 2400 series.
- With 1600 bpi operations, single track defects
were corrected in flight without affecting tape performance.
- Through the use of IBM 2816 Switching Units, Model
1, and special features, up to 16 tape drives can
be switched on as many as four channels.
- The IBM 2401, Models 4, 5 and 6, had the following
performance characteristics:
| |
Model
4 |
Model
5 |
Model
6 |
| Data
rate (8 bit bytes per second) |
60KB/
120KD |
120KB/
240KD |
180KB/
360KD |
| Tape
Speed (inches per second)
|
37.5
|
75.0 |
112.5 |
| Nominal
IRG Time (milliseconds) |
16.0 |
8.0 |
5.3 |
|
Rewind Time (minutes)
|
3.0 |
1.4 |
1.0 |
| Rewind
and Unload (minutes) |
2.2 |
1.5 |
1.1 |
|
Initial shipments of the improved 2401s from IBM's Boulder,
Colo., manufacturing facility began in August 1966, one
year after they were announced. More than 30,000 of these
tape drives were installed within the first four years
of their availability. |
