1.1 Flashcards
what is an input device?
a device that allows you to get information from the outside world so it can be processed and stored in a digital form
what are some examples of input devices?
keyboards, cameras, card readers, microphones, barcode scanners, mice, web cameras and remote controls
what is an output device?
a device which is able to take data which is stored in a digital form and convert it to another formant which humans can understand, eg. sounds, images and vibrations
what are examples of output devices?
speakers, headphones, printers, projectors, monitors
can some devices be both input and output devices?
yes, some devices such as games console can be considered both an input and an output device. In this case, the games console inputs the buttons pressed on the console by the user and outputs vibrations
what is a storage device?
any computing hardware, which is used for either temporary or permanent storage of data. This can be internal or external to the computer
what are example of internal storage devices?
magnetic hard drives, solid sate hard drives, RAM, ROM
what are example of external storage devices?
DVDs , blue-ray disks, USB pens, SD cards, portable hard drives
what is a magnetic storage device?
magnetic devices are any devices which store data using magnetic fields
what are some examples of magnetic storage?
magnetic tapes, old floppy disks, and some hard disk drives
how does magnetic storage work?
a series of magnetic disks known as platters are magnetised. A read write head moves very close to the magnetic surface if the platter. These read write heads are able to detect and modify magnetics properties of the platter. The tiny changes are recorded as binary
what are the advantages of magnetic storage?
cheap, large storage capacity
what are the disadvantages of magnetic storage?
slow access speed, moving parts makes it fragile
what is an optical storage device?
any devices which uses markers which can be read by or written to by an optical laser
what are some examples of optical storage devices?
CDs , DVDs and blu-rays
how does optical storage work?
data is written to the surface of an optical disk using pits and lands. The disk has a transparent substrate at its base followed by a reflective metal layer which carries the actual information. It works by using a higher power laser which changes the chemical properties of sections of its surface. A laser set at a lower power is then used to read the disk back. It shines light onto the disk through the base and measures the amount of light reflected back. As the point where a pitt starts or ends the light is scattered and therefore it isn’t reflected as well. These changes in reflective and non-reflective areas are recorded as 1s and 0s
what are the advantages of optical storage
cheap, lightweight, portable
what are the disadvantages of optical storage?
slow access time, surface is prone to scratches
what is solid state storage?
solid state storage devices, are any devices, which store data directly onto silicon microchips
what are some examples of solid state storage?
USB, micro SD cards, portable hard drives
how does solid state storage work?
It uses flash memory. Data is stored even when the power is turned off(non-volatile). Data is read and written directly to blocks and pages on the silicon microchips
what are the advantages of solid state storage?
durable, fast access speeds
what are the disadvantages of solid state storage?
costly, limited read/write cycles
what does RAM stand for?
random access memory
what is RAM?
Its primary storage anda type of temporary main memory, its used to store data and programs the computer is currently using. Its much quicker to access data in RAM than it is the access data that’s being held in the computers hard drive or secondary storage.
what does RAM hold?
Typically RAM will hold the operating system(or the part of the OS being used), the programs the c3mputer is currently running + the data the computer is accessing.
why is RAM volatile?
RAM is volatile because it loses all its contents when the power is turned off. Data is stored as small charges of electricity in transistors that are on a circuit. This needs to be refreshed or the charge leaks out, hence why data is lost when the power Is switched off
what does ROM stand for?
read only memory
what is ROM?
Its a type of primary storage, it cant be changed by a program or a user. It is non-volatile so it retains its contents, even without power. They are embedded on the motherboard of a computer
what does ROM hold?
ROM, hold the boot sequence for a computer to start up
what is cloud storage?
it is storing data over the internet instead of a local storage device.
what are the advantages of using cloud storage?
data can be accessed anywhere with an internet connection, data can be easily shared (dont need to copy data onto portable storage devices) , often considered limitless from the point of view of the user
what are the disadvantages of using cloud storage?
expensive, slower access speed with slower access speeds
where is data being stored, in cloud storage?
data is usually being hosted at a large data companies or on large magnetic or solid state drives
what can virtual storage be referred to as?
virtual storage can also be referred to as the abstraction or separation of logical storage from physical storage
how does RAM help?
RAM helps enable multitasking. Multitasking means having several programs open and using them at the same time. This is done by copying data needed by the programs at the time so that it can be passed to the CPU when it needs to process that data. It also stores all the instructions from the programs that are open that the CPU will require for processing
how does RAM hold data?
it uses capacitors and transistors. capacitors can hold an electrical current, when it is holding a current it represents 1 when its not, it represents 0. A transistor acts like a switch that lets the computer read what is on the capacitor or empty/fill up a capacitor
