sheng/Memory

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Memory

Contents

  1. Pre-questions
  2. Slides
    1. Definitions
    2. Memory technology
    3. Volatile Memory and Non-volatile Memory
    4. RAM, ROM, BIOS, Memory Cache
    5. Kilobytes, Megabytes, Gigabytes, Terabytes
  3. Questions
    1. A gigabyte is roughly equal to one billion bytes. How many bits are contained in one billion bytes?
    2. How many bytes are contained in one megabyte?
    3. When your computer's speed begins to drop, which element of memory is likely overtaxed?
    4. Which kind of computer memory is the first to activate when you turn on your computer?

1. Pre-questions

  • Q: How does a computer tell you it needs more memory?
 A: It says byte me!
  • Q: Do computers remember things?



  • Q: How do computers remember things?

2. Slides

2.1. Definitions

  • In computing, memory refers to the state information (a unique configuration of information in a program or machine) of a computing system, as it is kept active in some physical structure.


  • Q: What is the difference between Memory and Data Storage?


2.2. Memory technology

In the early 1940s, memory technology mostly permitted a capacity of a few bytes. The first programmable digital computer, the ENIAC, using thousands of octal-base radio vacuum tubes, could perform simple calculations involving 20 numbers of ten decimal digits which were held in the vacuum tube accumulators.


From images.yourdictionary.com on June 25 2017 04:24:29.

This magnetic drum unit was the memory in the IBM 650 computer, introduced in 1954. It held two thousand 10-digit words. That much memory today would fit inside the period at the end of this sentence.

2.3. Volatile Memory and Non-volatile Memory

  • Volatile memory is computer memory that requires power to maintain the stored information. Current semiconductor volatile memory technology is usually either static RAM (see SRAM) or dynamic RAM (see DRAM).

DRAM

  • Non-volatile memory is computer memory that can retain the stored information even when not powered. Examples of non-volatile memory include read-only memory (see ROM), flash memory, most types of magnetic computer storage devices (e.g. hard disks, floppy discs and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards.

Hard Disk

2.4. RAM, ROM, BIOS, Memory Cache

2.5. Kilobytes, Megabytes, Gigabytes, Terabytes

3. Questions

3.1. A gigabyte is roughly equal to one billion bytes. How many bits are contained in one billion bytes?

A. 1 billion bits
B. 2 billion bits
C. 4 billion bits
D. 8 billion bits
E. None of the above

3.2. How many bytes are contained in one megabyte?

A. 26 bytes
B. 212 bytes
C. 218 bytes
D. 230 bytes
E. None of the above

3.3. When your computer's speed begins to drop, which element of memory is likely overtaxed?

A. RAM
B. ROM
C. flash memory
E. None of the above

3.4. Which kind of computer memory is the first to activate when you turn on your computer?

A. RAM
B. ROM
C. BIOS
E. None of the above
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