500300 Rev. U
Preventative Maintenance
6-7
6.
Erased Areas on the Tape
- The more erased areas a tape contains, the less
data it can hold.
6.6.1
Data Capacity Tables
The following tables, showing the data capacities in megabytes for various length
tapes, assume a constant block length, no filemarks, and standard gap lengths.
NOTE
While all 34XX tape drives are capable of reading or writing data blocks of any length, not all
computers are equally capable. A maximum data block size of 32768 bytes is generally
acceptable, but some computers have maximum limits as low as 2048 bytes (the maximum size
specified by ANSI).
Length (ft):
300
600
1200
2400
3600
Density
MEGABYTES
1600 CPI
5.8
11,5
23.1
46.1
69.2
3200 CPI
11.5
23.0
46.1
92.2
138.4
6250 CPI
22.5
45.0
90.0
180.0
270.0
Table 6-1 Unformatted Tape Capacities
Length (ft):
300
600
1200
2400
3600
Block Size
MEGABYTES
80
0.4
0.8
1.6
3.2
4.8
128
0.6
1.2
2.4
4.9
7.4
256
1.1
2.2
4.4
8.9
13.3
512
1.8
3.7
7.4
14.9
22.3
1024
2.8
5.6
11.2
22.5
33.7
2048
3.8
7.5
15.1
30.2
45.3
4096
4.6
9.1
18.3
36.5
54.9
8192
5.1
10.2
20.4
40.7
61.1
16384
5.4
10.8
21.6
43.2
64.8
32768
5.6
11.2
22.3
44.6
66.9
Table 6-2 Formatted Tape Capacities, 1600 CPI
Length (ft):
300
600
1200
2400
3600
Block Size
MEGABYTES
80
0.4
0.9
1.7
3.4
5.1
128
0.7
1.3
2.7
5.4
8.1
256
1.2
2.5
5.1
10.2
15.2
512
2.3
4.6
9.2
18.3
27.4
