Information Technology Reference
In-Depth Information
7.9 Exercises
7.9.1
What is the maximum number of devices that can connect to a standard SCSI bus:
(a)
1
(b)
4
(c)
7
(d)
8
7.9.2
How many data bits does the SCSI-I bus use:
(a)
8
(b)
16
(c)
32
(d)
64
7.9.3
How many data bits does the SCSI-II fast/wide bus use:
(a)
8
(b)
16
(c)
32
(d)
64
7.9.4
How is device priority implemented on the SCSI bus:
(a)
by active polling
(b)
by interrupt priority
(c)
by brute force
(d)
by unit IDs
7.9.5
What method does the SCSI bus use to prevent devices from hogging the bus:
(a)
Time-outs
(b)
Interrupts
(c)
Active polling
(d)
Memory mapping
7.9.6
The transfer clock for a SCSI bus is 20 MHz. Which is the transfer rate for a 16-bit
data bus:
(a)
10 MB/s
(b)
20 MB/s
(c)
40 MB/s
(d)
80 MB/s
7.9.7
Explain the main differences between SCSI-I, SCSI-II and ultra SCSI. Outline
their maximum data throughput, the connectors used and the size of their data bus-
ses. Also, outline some of the advantages of SCSI over busses such as the ISA
bus.
7.9.8
State the SCSI lines that are used for simple error detection. Why is it not possible
to detect which bits are in error?
7.9.9
Discuss the main system lines that are used in the SCSI bus and the operation of
OR-tied driven signals.
7.9.10
Outline the main phases that the initiator and target go through in setting up a con-
nection. Also, outline the importance of device time-outs for the different SCSI
phases.
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