t-test Parametric test Biostatics and Research Methodology
Virtual memory gcse computing
2. VIRTUAL MEMORY IS PART OF THE HARD DRIVE USED AS AN EXTENSION TO RAM. IT IS
USED WHEN THE COMPUTER DOES NOT HAVE ENOUGH RAM TO HOLD ALL THE DATA
AND PROGRAMS REQUIRED.
DATA IS PASSED BETWEEN RAM AND VIRTUAL MEMORY – ACCESS TO VIRTUAL
MEMORY IS SLOWER THAN TO RAM.
ADDING MORE RAM REDUCES THE USE OF VIRTUAL MEMORY AND IMPROVES THE
PERFORMANCE OF THE COMPUTER.
IT USES SECONDARY STORAGE TO HOLD PARTS OF A PROGRAM THAT ARE NOT
CURRENTLY NEEDED.
3. • A LARGE PROGRAM MAY TAKE UP TOO MUCH MEMORY SO IT IS DIVIDED INTO
MODULES.
• THE MODULES ARE STORED SEPARATELY ON SECONDARY STORAGE
• WHEN A MODULE IS NEEDED, IT IS LOADED INTO MEMORY AND RUN AS A
PROCESS
• WHEN A DIFFERENT MODULE IS NEEDED IT CAN OVERWRITE AN UNUSED
MODULE