Seagate 1680 Computer Drive User Manual


 
1.4 Physical characteristics
Marathon 2250 Marathon 1680
Maximum height (inches)
(mm)
0.676
(17.2)
0.676
(17.2)
Maximum width (inches)
(mm)
2.76
(70.1)
2.76
(70.1)
Maximum length (inches)
(mm)
3.955
(100.45)
3.955
(100.45)
Typical weight (ounces)
(grams)
7.19
(204)
7.05
(200)
Note.
Maximum length excludes I/O connector pins that may extend up
to 0.015 inches beyond the edge of the head/disc assembly, per
SFF 8004 specification.
1.5 Seek time
All seek times are measured using a 25 MHz 486 AT computer (or faster)
with a 8.3 MHz I/O bus. The measurements are taken with nominal power
at sea level and 40°C ambient temperature. The specifications in the
table below are defined as follows:
Track-to-track seek time is an average of all possible single-track
seeks in both directions.
Average seek time is a true statistical random average of at least 5,000
measurements of seeks between random tracks, less overhead.
Full-stroke seek time is one-half the time needed to seek from the first
data cylinder to the maximum data cylinder and back to the first data
cylinder. The full-stroke typical value is determined by averaging 100
full-stroke seeks in both directions.
Seek type Typical read
(msec)
Typical write
(msec)
Track-to-track 4 5
Average 12 14
Full-stroke 26 28
Average latency: 6.65 msec
Marathon 2250 and Marathon 1680 Product Manual 7