1.6 MEMORY Flashcards
WHAT DOES MEMORY DO?
Memory is main memory/primary storage
Stores instructions. Accessed faster than secondary storage.
WHAT ARE THE IMPACTS OF MEMORY AND PROCESSOR ON PERFORMANCE?
-Affects speed at which software can be loaded
-Affects speed of completion of software tasks.
RAM
Random Access Memory.
WHAT DOES PROCESSOR DO IN RELATION TO MEMORY?
Processor fetches software instructions from memory and executes.
WHERE IS SOFTWARE LOADED FROM?
Loaded from computer’s secondary storage.
ROM
Read Only Memory. Memory that can NOT be changed after manufacture. Stores only one program.
WHAT IS ROM USED FOR?
ROM is ONLY used to boot the system and load to OS from secondary storage in PCs.
EXAMPLES THAT STORE ONLY ONE PROGRAM?
- Calculators
- Digital watches
- Washing machines
FEATURES OF RAM?
4
- Volatile - can NOT store data when it has no power = if power is off, all data in RAM is lost.
- Writing is fast
- Stores temporary data
- RAM can be upgraded using RAM slots on motherboard, can only add maximum supported by comuter.
WHAT HAPPENS IF SPACE IN RAM BECOMES FOR AVAILABLE?
Active programs are then moved into RAM from virtual memory which improves the performance of those programs. The computer system’s performance can be improved when user uses multiple files/programs at the same time.
FEATURES OF ROM?
- Non-volatile - data is NOT lost when power is off.
- Writing is slow
- Stores permanent data
- Can NOT be upgraded.
ARE RAM AND ROM ACCESSIBLE IN ANY ORDER?
YES
IMPACT OF SIZES OF RAM? (POSITIVE + NEGATIVE)
- If more RAM is available more programs can run at the same time. More complex tasks can happen, when updates happen, updates often include complex features.
- If there is not enough RAM, OS creates virtual memory by using an area of secondary storage.
WHAT ARE THE 2 TYPES OF ROM?
- EPROM (Erasable Programmable Read Only Memory)
- EEPROM (Electrically Erasable Programmable Read Only Memory)
WHAT IS EPROM?
Data from EPROM can be erased by exposing STRONG UV LIGHT. Can then be rewritten to it (reprogrammed).
WHAT IS EEPROM?
Data is erased by applying voltage to one of the pins on a ROM chip (applying a shock). By doing this, you DON’T need to remove ROM chip to erase its contents.
WHAT WAS EEPROM LATER DEVELOPED INTO?
Flash memory.
WHEN IS THE PROCESS OF ERASING/REWRITING DATA ON EPROM/EEPROM USED?
Used when updating firmware of device.
WHAT IS THE DIFFERENCE BETWEEN EPROM AND EEPROM?
EPROM data is erased by using STRONG UV LIGHT.
EEPROM data is erased by applying a voltage (shock).
CHARACTERISTICS OF FLASH MEMORY?
- Type of EEPROM
- Non-volatile
- Fast access time because of no moving parts.
- Lower power consumption because of no moving parts.
USES OF FLASH MEMORY?
- It is used in SSDs that is used in portable device which rely on internal batteries for power as it has LOW POWER CONSUMPTION.
- Often used as REMOVABLE STORAGE (USB drives, SD Cards)
WHAT IS SECONDARY STORAGE?
Storage. Slower than RAM, so when software then has to access instructions from virtual memory there is a great decrease in system performance.
WHAT HAPPENS WHEN SSD (Solid State Drive) IS USED AS SECONDARY STORAGE?
Data is swapped to and from
EXAMPLES OF SECONDARY STORAGE?
Hard disks, SSDs
