What is the portion of a computers primary storage does not lose its contents when one switches off the power?

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What is the portion of a computers primary storage does not lose its contents when one switches off the power?

This is a basic concept in computer science

The primary memory stores instructions. It is important to understand primary memory generally holds currently executing instructions.

There are two types of memory in primary memory, RAM and ROM[1]. For the IB, you should focus on RAM, and not ROM.

  • RAM is Random Access Memory which loses its contents when the computer is switched off (it is volatile ). This memory can be written to, instructions and data can be loaded into it.
  • ROM , or Read Only Memory is non-volatile and is used to store programs permanently (the start-up or " boot " instructions, for example), the computer cannot store anything in this type of memory.

When the programs and data files (known as the software) are not in RAM, they are stored on secondary storage (also known as backing store) such as tapes or discs. The tape or disc drives and any input and output devices connected to the CPU are known collectively as peripherals.

Primary Memory[edit]

RAM – Random Access Memory[2]

  • The RAM is where instructions, values are stored at runtime
  • The RAM can be accessed a lot faster than secondary storage, In general the time between primary memory and CPU is 7 to 10 nanoseconds.
  • All data and instructions are lost when the power is turned off (volatile)
  • Allows storage and random access to data and instructions
  • Each instruction & piece of data in the RAM has a unique address (see also: Operating Systems management techniques)

ROM[edit]

ROM – Read Only Memory

  • Can not be written to easily or at all (often times once only, then never again)
  • In modern PCs usually used for firmware in CPU, Graphics card, hard disks, etc.
  • Many ROM modules are replaced with Flash modules nowadays (ex. BIOS, firmware modules) to allow easier updating
  • In devices like keyboards, etc. which aren’t designed for firmware updates ROM might still be used
  • Stores code for interrupter

Video[edit]

Speed of primary memory[edit]

Please use this interactive latency tool to understand latency. Don't forget to move the slider to the right for the most current data.

Time comparison
unit of timeDefinitionSome examples
1 nanosecond Nanosecond is one billionth of a second. 1 ns: Time to execute one machine cycle by an Intel Pentium 4 1 GHz microprocessor, 1 ns: Light travels 12 inches (30 cm)
1 microsecond µs Microsecond is one millionth of a second. 1 µs: Time to execute one machine cycle by an Intel 80186 microprocessor
1 millisecond ms Millisecond is one thousandth of a second. 50-80 ms: The time taken to blink an eye
1 second 1 second is 1 second "One Mississippi" said aloud

Standard[edit]

  • Describe primary memory.

References[edit]

  1. http://www.ib-computing.net/program/core/memories.html
  2. http://dis-dpcs.wikispaces.com/2.1.2+Primary+Memory+and+2.1.3+Cache+Memory

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Memory

Primary storage is a key component of a computer system that enables it to function. Primary storage includes random access memory (RAM), read only memory (ROM), cache and flash memory. Each of these have different uses within the computer.

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Primary storage

Primary storage (also known as main memory) is the component of the computer that holds data, programs and instructions that are currently in use.

Primary storage is located on the motherboard. As a result, data can be read from and written to primary storage extremely quickly. This gives the processor fast access to the data and instructions that the primary storage holds.

There are four types of primary storage:

  • read only memory (ROM)
  • random access memory (RAM)
  • flash memory
  • cache memory

The two main types of primary storage are ROM, which is non-volatile, and RAM, which is volatile. Non-volatile memory keeps its contents even when the computer is switched off. Volatile memory loses its contents when power is lost.

Primary storage is comparatively limited in size, especially when compared with secondary storage. In a modern personal computer, primary storage is often around 4 GB in size.

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Which type of storage keeps your data even when the computer is turned off?

Secondary storage is non-volatile (retaining data when its power is shut off). Modern computer systems typically have two orders of magnitude more secondary storage than primary storage because secondary storage is less expensive.

Which part of the computer system refers to the primary storage?

Detailed Solution. The correct answer is Random Access Memory(RAM). Primary storage, also known as main storage or memory, is the main area in a computer in which data is stored for quick access by the computer's processor.

What is a primary storage device?

A primary storage device is any storage device or component that can store nonvolatile data in computers, servers and other computing devices. It is used to hold/store data and applications temporarily or for a shorter period of time while the computer is running.

What is the portion of a computer's primary storage does not lose its contents when one switches off the power?

Unlike RAM, Read Only Memory (ROM) delivers both non-volatile and permanent primary storage. ROM retains its contents even if the device loses power. You cannot change the data on it, you can only read it. ROM is a more reliable form of storage, and it will often boot instructions and other mission-critical data.