Here is an Abbreviation of direct memory access, a technique for transferring data from main memory to a device without passing it through the CPU. Computer that has DMA channels can transfer data to and from devices much more quickly than computers without a DMA channel can. This is useful for making quick backups and for real-time applications. Some expansion boards, such as CD-ROM cards, are capable of accessing the computer’s DMA channel. When you install the board, you must specify which DMA channel is to be used, which sometimes involves setting a jumper or DIP switch.
Why is DMA so important? Because it allows data to read and write form the DMA memory without intervention by the CPU. (CMOS setup and ROM Bios) Describe what the CMOS setup chip is used for in a personal computer? Personal computer contain a small amount of battery-powered CMOS memory to hold the date, time, and system setup parameters. Is the CMOS setup chip the same as the ROM BIOS? No they are different. If not, what does a ROM BIOS chip do in a personal computer? The BIOS is built-in software that determines what a computer can do without accessing programs from a disk.
On PCs, the BIOS contain all the code required to control the keyboard, display, disk drives, serial communications, and a number of miscellaneous functions. The BIOS is typically placed in a ROM ship that comes with the computer (it is often called a ROM BIOS). This ensures that the BIOS will always be available and will not be damaged by disk failures. It also makes it possible for a computer to boot itself. Because RAM is faster than ROM, though, many computer manufacturers design systems so that the BIOS is copied from ROM to RAM each time the computer is booted. Describe the different types of ROM technology used in ROM BIOS chips?
There are four types of ROM chips they are ROM, PROM, EPROM, and EEPROM/Flash ROM (EEPROM is also known as flash ROM). ROM is no longer in use that is what is found out. PROM is a blank chip on which data can be written with a special device called a PROM programmer. EPROM is a special type of memory that retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory. EEPROM/Flash ROM is a special type of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time.
Many modern PCs have their BIOS stored on a flash memory chip so that it can easily be updated if necessary. Another technology is ROM Shadowing for example, when you turn your computer it reads the BIOS and when it reads it form there it is passes it through the RAM because it is faster. Describe the difference between ROM chips and RAM chips? ROM (read only memory) chip is very slow and RAM (random access memory) chip is faster then ROM chip. On a ROM chip which data has been prerecorded it cannot be removed and it only can be read. In addition when you turn off your computer the data that was written will not lose its contents.
RAM memory can be access randomly that is any byte of memory can be access without touching the preceding byte; whoever, there are two basic types of RAM. They are dynamic RAM and static RAM. The two types differ in the technology they use to hold data, dynamic RAM being the more common type. Dynamic RAM needs to be refreshed thousands of times per second. Static RAM does not need to be refreshed, which makes it faster; but it is also more expensive than dynamic RAM. Both types of RAM are volatile, meaning that they lose their contents when the power is turned off.