Hardware

You will be able to

• Describe the fetch–decode–execute cycle using the PC, MAR, MDR, CIR and ACC, in register-transfer steps.
• State the purpose of the address, data and control buses, and which way each one carries its signals.
• Explain the stored program concept: instructions and data are held together in the same memory.

You will be able to

• Explain how the clock speed affects performance: more cycles per second means more instructions carried out each second.
• Explain how a larger cache improves performance: more data is found in the cache, so fewer slow trips to RAM.
• Explain why more cores do not always give a proportional speed-up: only the parts of a task that can run in parallel benefit.

You will be able to

• Describe how magnetic, optical and solid-state (flash) storage store and read data, using the terms track, sector, read/write head, pit, land, laser and NAND.
• Explain why a hard disk is slower to read a spread-out file than solid-state storage, in terms of seek time, rotation and moving parts.
• Choose a suitable secondary storage medium for a given use, justifying the choice by speed, capacity, cost, durability and portability.

You will be able to

• Describe how virtual memory is used when RAM is full: pages of data not currently needed are moved to an area of secondary storage.
• Explain why using virtual memory slows a computer down, including swapping pages back into RAM and disk thrashing.
• Explain why adding more RAM reduces the need for virtual memory.

You will be able to

• Describe a MAC address: 48 bits written as 12 hexadecimal digits, the first half identifying the manufacturer and the second half the device, set by the manufacturer on the network interface card.
• Explain the difference between a static and a dynamic IP address, and why a printer or a server is given a static one.
• Compare IPv4 and IPv6 addresses (32 bits in four denary numbers against 128 bits in eight groups of hexadecimal) and shorten an IPv6 address.