Flashcards
computing 1-4
Flashcards do conjunto (67)
- 1What is hardwarethe physical components of a computer system anything that can be seen or touched
- 2What can hardware include?inputs,outputs,storage and processing devices
- 3What is the processing of a computer program carried out by?CPU - central processing unit
- 4What is the CPU?The core of every computer system
- 5What does the control unit do?Control unit-uses electrical signals to direct the system to execute the instructions in stored programs
- 6What does ALU do?carries out all the arithmetic and logical operations including addition, subtraction and comparison
- 7In order to carry out these operations what does the CPU need access to?Main memory -RAM - random access memory, Where programs are stored. Cache memory- which is used to store data waiting to be processed
- 8What are cache memory and main memory called?primary storage-part the computer's processing capabilities
- 9What is secondary storage and give some examples?Hold data to be kept when the device is tuned off
Hard drives, flash memory drives,solid state drives - 10What is cache memory and why does it have dedicated connections to the CPU?very fast memory that sits close tot he CPU, so that the CPU has fast access to frequently used data
- 11Why do we usually use main memory and not cache?cache is quite expensive
- 12How does the CPU know whether it is looking at Instructions or data?If it expects data that is what it will assume it has and it will try to decide what it is and what to do next
- 13What will the CPU if it receives an instruction?An instruction has two parts (e.g an instruction,data, a number or memory location). The CPU has to decode in order to work out what to do next- CPU starts the Fetch decode Execute cycle
- 14Describe the fetch execute cycle?The CPU fetches the instruction it needs to process from main memory,decodes it and executes it before repeating the process
- 15What si the boot sequence?After the computer is switched on , the CPU will look at a specific place in ROM fro the first program to decode and execute. This is so the CPU knows where to find it. The CPU then begins the process of executing the program commands to get the computer up and running and get the operating system started
- 16What happens after the boot sequence is complete?hands the control to the operating system to provide the programs that the CPU needs to run
- 17What si the speed of the cycle determined by?clock chip
- 18How does the clock chip work?It uses a vibrating crystal that maintains a constant rate. It is measured in hertz or cycles per second. The computer synchronises all processes to this signal
- 19What does 3GHz mean?3 billion cycles per second
- 20What cant main memory not keep up with the clock speed, how does this create problems?It delays in locating and transferring data from main memory to the CPU
- 21Why is it so slow?The CPU has to wait for main memory to supply the data waiting to be processed which means the CPU is not working at its full capacity
- 22How deos the CPU overcome this?When the first instruction is requested by the CPU , the remaining instruction are automatically transferred to cache memory. This because cache memory has similar access time to the CPU. In order to improve the performance of the CPU it will go straight to cache memory for the next instruction to see whether is has been copied if it is not there then it will go to main memory
- 23How does looking at cache first speed up the process?reduces the time taken to access data making the process more efficient
- 24Why does having more cache improve this process?Because the more cache there is the more likely the required data has been copied
- 25What is 1GB1024 MB
- 26What are the two things that affect the speed or performance of a system? What can this be limited by?clock speed and cache memory
The speed of data and control signals can move around the system. - 27How do Data and control signals move around a system ?by buses
- 28What is a bus?a circuit that connects one part of the motherboard to another. Transfers data and signals between the components of the computer
- 29What is the speed of buses usually measured in?usually measured in megahertz (millions of cycles per second), refers to how much data can move across the bus at the same time.
- 30Give an example of another way to improve the performance of a computer systemMulti-core processor, A dual core processor has two CPU's working together. The both have their own cache and can fetch decode and execute instructions at the same time as one another , so the computer is able to process more instructions as a whole
- 31What is the motherboard?The central printed circuit board the holds the crucial components of the system.
- 32What is ROM?A store of data in a computer that cannot be over written. It is always available and not lost when the computer is turned off
- 33Memory What is a bit? What is a byte? what is a kilobyte?Binary digit 0 and 1
8 bits
1024 bytes - 34What does volatile mean?Data is lost when there is no power
- 35What is ram? How does Ram improve the performance of your computer?main memory,Ram is required for operating system,loaded applications and any data that is currently in use
More ram the more data and programs can be loaded at the same time - 36How is a program loaded? What does this allow the cpu to do?copied from a hard disk or other device to main memory. The cpu is then able to access data and instructions for the program as required
- 37Why is data copied from secondary storage? Why do we have secondary storage?because access to it is very slow.
It holds files and programs because RAM is volatile and and data is lost when the power to the computer is switched off - 38How does a RAM chip work? How is ROM formed?they use transistors to hold charge that represents data but requires power to maintain this charge.
By connecting resistors together in a specific way they can remember what they were storing.It is able to retain information programmed in by the manufacturer - non volite - 39What is Rom used for?Stores the boot sequence, cant be overwritten by the computer
- 40What is virtual Memory? When is it used?A section of the hard dik used as if it were ram to supplement the amount of main memroy available to the computer.
When there is not enough main memory to run the programs required - 41Why can it make switching between programs slower?the computer has to move data between memory and the hard disk before it can open the secondary program or continue with another section of the program or data.The cpu is spending more time switching between components rather than processing data
- 42Why can having more main memory improve the performance of the computer?more of the data and parts of the programs can be directly available to the cpu. The user will also be able to uuse more programs at the same time,The performance will be improved to the programs that require more data.
- 43What is Dynamic RAM?One of two types of ram-has one transistor and a capacitor that can hold a small charge for a few milliseconds to represent one bit. In order to maintain the charge in the capacitor it needs to be refreshed every few milliseconds.
- 44What is static Ram?RAM chips are more complicated and use four or five transistor wired together four ech bit but they do not lose their charge, they can store data without it being refreshed. Access to data is much faster and they are used for cache
- 45Why dont we use static ram all the time?fewer bits per chip and more complicated manufacture-costs more
- 46How does flash memory work?Rom than can be rewritten by erasing contents or parts of contents, uses a relatively large electric current to force electrons through a barrier and trap them in a layer on the other side of the barrier until they are reset. This creates a flash
- 47Give some examples of what flash memory can be used for?cameras, usb memory sticks, main secondary storage in portable devices andon large installation. There are some limitation on there uses such as detorioration
- 48Give some advantages of flash memory?low cost, portable and removable storage for a number of devices. Typical capacity ranges up to 256gb
- 49Give some disadvantages of flash memory?flash memory is not as fast as ram but it is faster than a magnetic hard disk. Can be used as additional drive to back up or supplement or back up a portable computer
- 50What is a system? What are interconections?A collection of parts that work together for a common purpose
interconnection between system are called interfaces - 51What is a system boundry?separates what is a system from what is not. this can be difficult to define when some systems are part of other systems
- 52What do computer systems do?process data and produce information. they are electronic Which makes them fast and they are programmable. This means the computer system can be made to do many thing depending on what instructions we give it
- 53What does dedicated systems mean? what does general purpose systems mean?something that is designed for one particular purpose. Software can also be deicated for a particula device and sitution that it controls
they can be used for different reason depending on what needs to be done - 54What is an embedded sytem?A computer system that forms part of an electrical device mostly dedicated
- 55What happens if a general purpose sytem supports dedicated software applications?reduces the effort needed to write software for a device, because much of its functionality is borrowed from the operating system. e.g media players , smart phones (all are Linux kernel)
- 56What is a kernel?lowest level of the operating system that controls the hardware.
- 57Reliability Give examples of what can happen if a system is not reliable?down time
e pensive errors
data loss
compromised privacy - 58what is data integrity?data being accurate and consistent throughout its life
- 59How can data integrity be compromised?human errors when data is entered
errors that occur when data is transmitted from one computer to another
software bugs and hardware malfunctions
natural disasters
viruses and other malware - 60Why can testing never be complete?software is so complex
testing is expensive
testing is time consuming - 61Why do we test data?To uncover errors
- 62Standards Why do we have standards?to make systems more reliable, more likely to be successful and satisfy user's. It also helps make sure that different computer systems can talk to each other.
- 63What is a proprietary standard? And give some advantages-Standards own be a company
all systems will look and feel familar to the users and will speed up the learning process
work in a predictable way, which will in-turn improve reliability
be maintained by one company although there will different versions of the software, versions that contain minor updates are usually free - 64What is a industry standard? And give some advantages-agreed across the computing industry. Many relate to hardware and allow interconnection between devices
- 65What is a De facto standard standard? And give some advantages-standards that develop through common usage until they are an accepted way of making of doing things
HTML-started as a proprietary standard and as it gained popularity it eventually becam a de jure standard(means you must adopt it if you wnat to communicate with somebody else - 66...PDF- proprietary standard created by a company called adobe but copyright was handed over too international organisation of standardisation in order to make movement of digital file more open making it free and it became more common.
- 67What is a open standard?standards that are publicly available to users and can be modified by users