Read and memorize the words:
- to store
- to avoid
- to access
- to reduce
- to retain
- to erase
- to turn off
Read and translate the text
A computers memory can be viewed as a list of cells into which numbers can be placed or read. Each cell has a numbered “address” and can store a single number. The information stored in memory may represent practically anything. Letters, numbers, even computer instructions can be placed into memory with equal ease.
In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits(called a byte). A computer can store any kind of information in memory as long as it can be somehow represented in numerical form. Modern computers have billions or even trillions of bytes of memory.
The CPU contains a special set of memory cells called registers that can be read and written to mach more rapidly than the main memory area. There are typically between two and one hundred registers depending on the type of CPU. Registers are used for the most frequently needed date items to avoid having to access main memory every time data is needed. Since data is constantly being worked on, reducing the need to access main memory greatly increases the computers speed.
Computer main memory comes in two principal varieties: random access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it , but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computers initial start-up instructions. In general, the contents of RAM is erased when the power to the computer is turned off while ROM retains its data indefinitely.
Answer the questions:
- What does memory consist of?
- What has each cell?
- What may the information stored in memory represent?
- How long can computer store any kind of information?
- What is called register?
- What are registers used for?
In contrast to memory, storage provides a place to store data and programs before and after processing.
Disk have become the most widely used medium for the storage part of the system. A disk is a circular platter on which a recording surface has been applied . The most common type of disk is magnetic. It is coated with the same material found on audiotape, and it can be erased and used over and over. Another type, the optical disk, uses laser beams of light instead of the magnetic method to record and retrieve information. There are two types of magnetic disk and hard disk. Floppy disk are made from thin sheets of flexible plastic: hard disk are made from rigid platters of metallic or ceramic material. The device that plays the disk is called a disk drive. \it contains the mechanical equipment needed to spin or rotate the disk and the read write head needed to record and retrieve information to and from the disk.
Hard disk drives are large-capacity storage devices. They operate by the same principles as floppy disk drives, but at much faster speeds. Their capacities are measured in megabytes. The hard disk is used for storing large quantities of information and provides fast access to that information. The floppy disk drive is convenient for making backup copies of the data on the hard disk, making copies of files that can be mailed to friends or co-workers, and of course, for putting new programs and information into the computer.
Answer the questions:
a.) What is storage? Give the definition in your own words.
b.) What is the most widely used medium for storage?
c.) What types of disk can you list?
d.) What type are floppy and hard disk? What is the difference between them?
e.) What devices are needed to record and retrieve information to and from the disk?
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