Unit 1 - System Architecture Flashcards
What is an input device?
An input device is a device that gives a signal to the computer.
What is an output device?
An output device is a device that receives a signal from the computer and outputs something.
What is a processing device?
A processing device processes instructions and executes them.
When was Von Neumann architecture discovered?
Von Neumann architecture was discovered in 1944.
What does Von Neumann architecture involve?
Von Neumann architecture involves storing the program instructions and the data the programs are using in the same memory.
Name the two major units in the CPU.
The two main components in the CPU are the Control Unit and the Arithmetic-Logic Unit (CPU).
List the order of speed for data stores in the CPU. (fastest to slowest)
In order to fastest to slowest, the order of speed for data stores in the CPU is registers, cache and RAM.
Name four registers in the CPU.
Four registers in the CPU are the Program Counter (PC), the Memory Address Register (MAR), the Memory Data Register (MDR), and the Accumulator.
What does the program counter do?
The program counter holds the address for the next instruction to be executed.
What does the Memory Address Register do?
The Memory Address Register holds the memory address of the current instruction and then the data that it uses, so that these can be fetched from memory.
What does the Memory Data Register do?
The Memory Data Register holds the actual instructions and then the data that has been fetched from memory.
What does the Accumulator do?
The accumulator holds the result of an instruction before it is transferred to memory.
What does the Control Unit do?
The control unit coordinates and controls all of the activities taking place within the CPU. It also decodes instructions and executes them, it receives signals from the system clock and it directs the timing and control of other parts of the CPU.
What does the Arithmetic Logic Unit do?
The ALU is where the actual arithmetic operators are done. It also carries out logical operations such as AND, OR and NOT.
What is the name of the three operations that the CPU operates by?
The three operations are Fetch, Decode and Execute.
What happens in the Fetch part of the Fetch-Execute cycle?
In Fetch, the next instruction and any data involved is fetched from main memory.
What happens in the Decode part of the Fetch-Execute cycle?
In Decode, the instruction is decoded.
What happens in the Execute part of the Fetch-Execute cycle?
In Execute, the instruction is executed.
What does the Program Counter hold?
The program counter holds the address of the next instruction to be executed.
What is the purpose of the CPU?
The purpose of the CPU is to fetch and execute instructions stored in memory.
What is a register?
The register is a special, fast memory location in the CPU.
Name four special registers in the CPU.
The Program Counter, the Memory Access Register, the Memory Data Register and the Accumulator.
What affects a CPU’s performance?
CPU performance is affected by the clock speed, the number of cores and the size of the cache.
What is an embedded system?
An embedded system is a single microprocessor that includes RAM, ROM and a CPU.
Name examples of an embedded system.
Some example of an embedded system are satnavs, microwaves, dishwasher, burglar alarm, washing machine, digital watch.
What are the two main types of primary storage?
The two main types of primary storage are RAM (Random Access Memory) and ROM (Read Only Memory).
What does the RAM store?
The RAM stores the operating system when in use, the software in use and the data being used by software.
What happens to the data in the RAM when there is no power?
The data in the RAM is lost if there is no power as it is volatile.
What happens when the RAM is full?
When the RAM is full, data is offloaded onto the Virtual Memory in the hard drive.
What data is stored in the ROM?
In the ROM, the BIOS and bootstrap are stored.
What does RAM stand for?
RAM stands for Random Access Memory.
What does ROM stand for?
ROM stands for Read Only Memory.
State one difference between RAM and ROM.
RAM: volatile, higher capacity, can be written to
ROM: non-volatile, lower capacity, cannot be written to
Why is virtual memory slower than RAM?
Virtual memory is slower than RAM as it is longer for the CPU to access the hard drive than the RAM.
What is secondary storage?
Secondary storage is a non-volatile storage device that is not directly accessable by the CPU. It can be internal or external to the CPU.
Explain the magnetic method of storage.
Magnetic storage has mechanical moving parts which move over the disk’s surface to read and write data magnetically.
Explain the optical method of storage.
Optical storage uses lasers to read and write data using light.
Explain the solid state method of storage.
Solid state storage has data recorded onto solid memory chips without any moving parts.
What are the advantages of magnetic storage?
- Cheap
- Large storage capacity
- Relatively fast write speed
What are the disadvantages of magnetic storage?
- Lots of mechanical parts
- Low durability
- Sealed unit so cannot be repaired
- Not very portable
What are the advantages of optical storage?
- Cheap
- Very easily portable
- Takes up very little space
What are the disadvantages of optical storage?
- Less storage capacity compared to other types
- Easily damaged
- Requires a reader
- Slow write speeds
What are the advantages of solid state storage?
- Highly durable
- No moving parts
- Very fast read/write speeds
- Quiet
- Fast startup times
What are the disadvantages of solid state storage?
- Expensive
- Similar storage capacity as magnetic disks
