What do you gain with SCSI

What do you gain with SCSI?

Answer:

Expensive but good: SCSI makes the PC a little more expensive, but much better. That's all. The
advantages are, that on the same PC you have free access to use many units and good hard disks:
*It is easy to add many high end accessories, such as DAT-streamers, CD-ROM recorders,
MO drives, scanners, etc.

*You can use SCSI hard disks.
*You can use CD-ROM drives on SCSI , where they perform a lot better than on IDE.

Advantages of SCSI hard disks

SCSI hard disk are generally of higher quality than other disks. EIDE disks come in various qualities from
different manufacturers. However, even the best EIDE disks cannot compete with the best SCSI disks.
Typically, good SCSI disks come with a 5 year warranty. They come in larger capacities than the EIDE
disks and they are faster. At 5400, 7200 or 10.000 RPM they have shorter seek times. They also have a
bigger cache.
Another advantage is the large number of accessories, which can be attached. If you buy a 4 GB SCSI
disk today, you will guaranteed need additional disk storage in a few years. Then you just add disk
number two to the SCSI chain, and later number three. The system is more flexible than EIDE, where
you can have a maximum of four units incl. CD-ROM.
The SCSI hard disks can also adjust the sequence in the PC's disk read commands. This allows to read
the tracks in an optimal sequence, enabling minimal movements of the read/write head. Quantum calls
this technology ORCA (Optimized Reordering Command Algorithm). It should improve performance by
20%.
Finally, the SCSI controller can multitask, so the CPU is not locked up during hard disk operations, which
you can experience with IDE.
SCSI hard disks can achieve substantially larger transfer capacity than the IDE drives, but they have the
same bottle necks: the serial handling of bits in the read/write head, where the capacity is highly
dependent on the rotation speed.