Main Focus Points Flashcards
(58 cards)
What are the advantages of hexadecimal?
More compact representation.
Easier to understand.
What are the advantages of fixed point representation?
Faster processing
More accurate/ precise.
What are the advantages of floating point representation?
Can represent a larger range of numbers with the same number of bits.
What is the stored program concept?
Instructions are stored as data in main memory and the processors fetches and executes them sequentially.
What is sampling resolution?
How many different graduations of amplitude can be represented.
What are the advantages of normalisation?
More accurate representation for a given number of bits.
Unique representation of each number.
What is lossless compression?
When files are decompressed the original data is reproduced without any loss.
What makes up system software?
OS
Utility programs
Libraries
Translators.
What are utility programs?
Programs that perform specific tasks related to the running of the computer.
Security - antivirus software, firewalls
Disk organisation - defragmentation, free up disk space
System maintenance - managing files, compression
What is byte-code?
An intermediate step between source code and machine code, that allows for interpretation according to the architecture of the machine as and when it is required.
What is a register?
A small section of temporary storage apart of the processor, that store data or instructions during the FDE cycle.
What are the functions of the OS?
F - Organises files into directories.
U - Hides complexities of the hardware from the user
M - allocates cores to processors and manages the execution of multiple processes.
P - manages communication byeweeen processes and I/O devices.
Sn- manages updating software.
Advantage of assembly code?
More control over the final machine code executed.
What is fetch part of the FDE cycle?
PC holds the memory address of the next instruction to be fetched.
Memory address is loaded into MAR from the PC by the processor.
Processor sends the address to main memory via the address bus.
The contents of the memory address are loaded into the MBR by the data bus.
Contends of the MBR loaded into CIR by data bus.
PC incremented.
What is decode part of the FDE cycle?
Decode instruction is held by the CIR.
Control unit decodes the instruction by splitting it into the opcode and operand and using its instruction set.
What is the execute part of the FDE cycle?
Processor carries out the instruction.
If necessary data is fetch from/ stored to main memory
Result of any calculation is stored in the accumulator or registers.
Status register updated.
Go over hardware items.
Barcodes, camera etc,
How do hard disks work?
They are made up of multiple disks made of metallic material, arranged in a stack.
The disks are coated just a thin film of magnetic material.
Changes in the direction of magnitude represent 1’s and 0’s
The disks spin and heads read from of write to the disks.
The surface of the disk is organised into concentric tracks, which are split into sectors which can be individually addressed.
How do solid state drives work?
They use a type of programmable ROM chip, NAND memory.
NAND memory is made up of semi-conductors.
Data is organised into blocks, where a controller manages the blocks.
Semi-conductors retina their data without power because of a floating gate transistor, which is a floating gate coated in an oxide layer that traps charge, between a control gate and a silicon substrate.
What is the difference between static RAM and dynamic RAM?
Static RAM uses several transistors per bit of memory, where are dynamic RAM uses one.
On the system bus diagram what are the 5 sections?
Processor
Keyboard Input Controller
VDU Output Controller
Disk I/O
Memory
What is the cache?
Very small, fast memory within the CPU that stores regularly used data and instructions.
What are the advantages and disadvantages of synchronous data transmission?
Adv - allows communication in real time, reduced timing errors if properly synchronised, faster
Dis - expensive, and requires clocks to be synchronised.
What are the advantages and disadvantages of asynchronous data transmission?
Adv - easier to implement, flexible, cheaper
Dis - timing errors, increased overhead, slower