part 3, Hardware and software concepts Flashcards
this is a fixed length of bits
what is a word
give an overview of what happens during decode
- the control unit finds out what instruction is being held in the operator part of the instruction register and then sets up the necessary circuits and values for the instruction to take place
in detail what happens during the fetch
- The control unit sends a control signal on the control bus to the program counter telling it to put the address that it holds onto the address bus so that that location in memory can be read
- A memory read control signal is then sent to memory. This causes the data held in in the location being accessed to be put onto the data bus
- The control unit then ensures that the data is routed to the instruction register

how many bytes in a tebibyte (TiB)
this contains
240 bytes
what is the sample rate
this is how many samples are being taken per a second
what is a word
this is a fixed length of bits
what are the 2 jobs of the accumulator
- this has the job of storing numbers that are about to be used in an arithmetic operation.
- it also has the job of storing the output value of the operation just performed which can then be held for the next operation or sent back to main memory
- The control unit then sends an execute control signal to any component involved in the instruction so that that unit can carry out its work and load any values to there appropriate register such as the accumulator
- A control signal is then sent to the program counter to increase the counter by 1
- The cycle then repeats
what happens during execute
the bits that are held by this might tell you that the outcome of the last operation
- the integer was negative/positive
- was to large or too small to hold in the accumulator
what type of information might the bits held in the status reister tell you
explain what Just in time (JIT) compilation is
with this if a block of code is used frequently then it is compiled to machine code by the virtual machine and stored in cache. This eliminates the need for any further interpretation on the given block of code
- this follows a fetch-decode-execute cycle.
- is in charge of sending out control signals so that data may find its way from main memory to the cache and registers and then to the appropriate unit
- holds an instruction set and compares instructions when decoding them
what are 3 features of the control unit
this stands for
Complex instruction set computing (CISC)
what does CISC stand for
where can the status register be found and what is its role
- this can be found within the processor
- its role is to hold a report on the outcome of the last executed instruction
how many bits does one hexadecimal digit hold
this holds 4 bits (nibble)
this does not produce object code or an object program instead it only translates instructions as and when they are needed
how does an interpreter work
is usually expressed in bits per second (bps) or kHz
how is the bit rate usually expressed
this holds the memory address of the next instruction and then when told by the control unit it will increment this address by one (this happens after execution but before fetching). if the control unit is told to jump to an address then the value will be held here
what is the role of the program counter
this part holds the instruction that the control unit will decode
explain the operator part of the instruction register
multi core processors give of less heat. why is this
the reason these give of less heat is because more heat is generated when a processor has to constantly switch between tasks. when a processsor can focus on one task it in turn will dissipate lesss heat
- The control unit sends a control signal on the control bus to the program counter telling it to put the address that it holds onto the address bus so that that location in memory can be read
- A memory read control signal is then sent to memory. This causes the data held in in the location being accessed to be put onto the data bus
- The control unit then ensures that the data is routed to the instruction register

in detail what happens during the fetch
- When a program is written knowledge of the processor is not needed and does not need to be coded into the program
- When a program is written knowledge of peripherals is not needed. This is handled by the operating system who holds device drivers that tell it how to operate different peripherals
- The operating system can handle memory management and ensure that two programs do not disturb/overwrite each other
- The operating system can orchestrate multiple programs running simultaneously
name 4 benefits that an operating system gives
what is an instruction set
this is a set of instructions that the processor understands and can execute
this holds 4 bits (nibble)
how many bits does one hexadecimal digit hold
this makes itslef more effiecient by
- predicting what instructions will need to be processed next
- using instructions that directly make this more efficient
- having a good management system for this
- loading large sequence of instructions into itself where possible
what 4 ways is cache made more efficient















