For each question (1-5), circle the most reasonable (best) answer. (1 mark each)

(1) A very fast modem can transfer data at a speed of :

[1 MB per second] . . . . . [1 KB per second] . . . . [50 Kb per sec] . . . . [50 KB per sec]

(2) A typical hard-disk in a PC can transfer data at a maximum speed of:

[5 MB per second] . . . . [5 KB per second] . . . . [100 KB per sec] . . . . [100 MB per second]

(3) A typical RAM chip in a PC can retrieve a single byte in:

[1 nanosecond] . . . . [60 nanoseconds] . . . . [10 microns] . . . . [66 MHz ]

(4) A typical typist can use a keyboard to transmit:

[1 KB per sec] . . . . [1 Kilobit per second] . . . . [1 bit per second] . . . . [2 bytes per sec ]

(5) A typical Pentium CPU runs at a speed of:

[66 MHz] . . . . [66 MB] . . . . [166 Mb] . . . . [233 MHz ]

Fill in the blanks (questions 6-10). (1 mark each)

(6) A 32-bit data bus running at 66 MHz can transfer approximately ___________ MegaBytes per sec.

(7) A 64 Kb modem, under very best conditions, needs approximately ____________ minutes to download a 10 MegaByte file.

(8) POTS stands for _________________________________________________________.

(9) Many devices must warm up or do something else before they can actually perform a task.
The technical term for time spent waiting for a process to start is ____________________.

(10) One example of a bipolar device is a __________________________ .

True or false? (questions 11-15, 1 mark each)

(11) All components in a computer run at the same speed (frequency). ________________

(12) Reducing the width of a data-bus to 8 bits would make the bus faster. ________________

(13) A buffer is a temporary storage area - most printers contain buffer memory. ________________

(14) ASCII codes are numbers which represent letters or other characters. ________________

(15) You should not run a microprocessor at a higher frequency than specified,
because it may get to hot and break. ________________

Answer question (16) on a separate sheet of paper - it counts 10 marks.

(16) Internet access is basically too slow for most people - they spend a lot of time waiting for HTML pages to appear on the screen, or for software or pictures to be downloaded from a web-site. The basic problem is bandwidth.

• Explain what bandwidth means.

• Give typical values for the bandwidth of each of the following devices:

a modem . . . . . . . . . a network cable . . . . . . . . . . . a data-bus on a PC motherboard

• The use of optical fiber might speed up the Internet. Explain why optical fiber could help.

• Unfortunately, we cannot all switch over to optical fiber immediately. Explain two practical problems which are slowing down the introduction of optical fiber.

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Choose FOUR of the following questions. Answer them on a separate page.

Write clearly and show any calculations. Each question is worth 5 marks.

(17) Explain Moore's Law, and why this is very important for the computer industry.

(18) Explain how compression can speed up computer operations, especially Internet access.
Also, describe a situation where compression could slow down computer operations.

(19) Explain how a memory cache is used to speed up computer operations. What do the terms "level-1" and "level-2" mean? If cache memory chips are faster than RAM chips, why not simply use these faster chips for the entire RAM?

(20) Describe how more transistors can be squeezed onto a microprocessor. Describe one physical problem caused by squeezing more transistors onto a chip.

(21) A typical movie is about 90 minutes long. It is displayed at 20 frames per second. Assume that the movie is being displayed at 640x480 pixels, using 16-bit color (16 bits used to store each pixel.)

Calculate the total storage requirements for the film (give your answer in GigaBytes), assuming that no compression techniques are used. Also, calculate the data-transfer-rate required to play the film,
giving your answer in MegaBytes per second.

(22) One method to speed up the performance of a hard-disk is to engineer it to spin faster.
How fast does a typical hard-disk spin? What engineering problems might be caused by doubling this speed?
Another possibility for speeding up hard-disks is to make them smaller. Explain why this would make a hard-disk faster.