What Are Screensavers For?Screensavers were originally designed to protect computer monitors from phosphor burn-in. Early CRT monitors, particularly monochrome ones, had problems with the same image being displayed for a long time. The phosphors, used to make the pixels in the display, would glow at...
Disk Access and Memory Access
A 25-MIPS machine can execute 200,000 instructions during the time it takes to access the disk once. A 25-MIPS machine, assuming one instruction per cycle, only runs at 25 MHz.
A hard-disk is like a very long line of buckets and each bucket holds a group of bytes. To keep track all of these buckets, some of the "buckets" are set aside to describe which buckets hold what file or chunks of a file just like the index . When the operating system deletes a file it usually just...
portal site : a site that the owner positions as an entrance to other sites on the internet; "a portal typically has search engines and free email and chat rooms etc."