Can someone explain this tutorial problem? I don\'t understand the multiplicatio
ID: 3563386 • Letter: C
Question
Can someone explain this tutorial problem? I don't understand the multiplication factors for each and how they get the specific answers.
Will reward.
A 32-bit computer has two selector channels and one multiplexor channel. Each selector channel supports two magnetic disk and two magnetic tape units. The multiplexor channel has two line printers, two card readers, and five VDT terminals connected to it. Assume the following transfer rates.
Disk drive 700 Kbytes/s
Magnetic tape drive 200 Kbytes
Line printer 6.6 Kbytes/s
Card Reader 1.2 Kbytes/s
VDT 1 Kbytes/s
Estimate the maximum aggregate I/O transfer rate in this system.
Explanation / Answer
For Selector channel
only one device can be serviced at selector channel
for maximum rate we want that device with maximum rate to be serviced.
Hence , for two selector channel , we will service two magnetic disk (one for each selector channel as disk has the maximum transfer rate out of disk and tape)
Transfer rate by selector channel = 700+700 Kbytes/s = 1400 Kbytes/s
For multiplexer channel
a multiplexer channel can serve any number of device(depending on its Multiplexing capacity)
hence , two line printers, two card readers, and five VDT terminals can be served at the same time
Transfer rate by multiplexer channel = (2*6.6) + (2*1.2) + (5*1) Kbytes/s
= 20.6 Kbytes/s
Total transfer rate = transfer rate by selector + transfer rate by multiplexer
= 1400+20.6 Kbytes/s
= 1420.6 Kbytes/s