Seagate 6451 Computer Drive User Manual


 
1.4 Physical dimensions
The mounting dimensions are shown in Figure 6 on page 23.
Height, max 1.027 inch (26.09 mm)
Width, max 4.025 inches (102.2 mm)
Depth, max 5.787 inches (146.99 mm)
Weight 1.5 lb (0.68 Kg)
1.5 Seek time
Seek value is the interval between the time the actuator begins to move
and the time the head has settled over the target track. Seek time is a
true statistical average of at least 10,000 measurements of seek time.
All measurements are taken under nominal conditions of temperature
and voltage with the drive mounted horizontally. The specifications in the
table below are defined as follows:
Track-to-track seek time is the average of all possible single-track
seeks in both directions.
Average seek time is measured by executing seeks in both directions
between random cylinders.
Full-stroke seek time is half the time needed to seek from track 0 to
the maximum track and back to track 0.
Track-to-track
seek time (typ)
Average/typical
seek time
Full-stroke
seek time (typ)
Average
latency
2.0 msec seek
2.5 msec read
3.5 msec write
9.5 msec read
10.0 msec write
20.0 msec seek
22.0 msec read
23.5 msec write
5.58 msec
Note.
Host overhead varies between systems and cannot be specified.
Drive internal overhead is measured by issuing a no-motion seek.
Overhead is typically less than 0.5 msec.
1.6 Multisegmented cache buffer
The Medalist Pro ST36450A and ST36451A drives are available with a
512-Kbyte, multisegmented cache buffer that improves performance by
reducing access times.
Read look-ahead.
The drive uses the read segments to store additional
logical sectors, after the last requested sector, into a buffer before the
computer requests the additional sectors. The cache buffer stores data
Medalist Pro 6450/6451 Product Manual, Rev. B 7