11/9/2013
CMOS
GERARDO ZUNIGA
The PC uses a special memory call, the CMOS (complimentary metal-oxide-semiconductor)
is the term usually used to describe the small amount of memory on a computer
on a motherboard that stores the BIOS
settings, such as the date, time, number of disks, amount of memory, video
type, including power on self-test (POST)
The first COMS chip was made by Motorola to be
used in early IBM computers it was capable of storing 64 bytes of data. The CMOS is powered by a small
battery, so when you turn off your computer it does not loses data, the
standard lifetime of a CMOS battery is around 10 yr. CMOS memory size has remained relatively unchanged over
the years there was never any need to store more than 512 bytes witch is the current typical size.
EEPROM
(Electrically Erasable Programmable Read-Only Memory) can be modify, red,
erased, and re-programed in its entirety but has a limited life, to or up to
hundreds of thousands of times. (Centurion, 200)
CMOS is SRAM
(Static Random Access Memory) that is manufacture with CMOS technology or
programmable memory it uses very little power so small battery is required.
Most new computer systems use EEPROM memory but Cmos memory still in use.
References
Itt-tech virtual library Siti Sarah Binti,
M., Mohamed, H., Mamun, M. d., & Syedul Amin, M. d. (2012). Cmos
Downsizing: Present Past and Future. Journal of Applied Sciences Research,
8(8), 4138.
Diference between CMOS and EEPROM http://arstechnica.com/civis/viewtopic.php?f=11&t=912720
(Centurion, 200)
THE BIOS
The bios is the first program activated in
the boot sequence it is permanent read only memory and cannot be edited, but
instructions or firmware can be changed to do this the bios uses a new
technology call EEPROM (Electronically Erasable Programmable Rea-Only Memory)
and by buying a new MOBO or Flushing the Bios, to get a new bios down load a
new updated copy of the bios or run the bios flash installer. The bios does not
need power to maintain its content a Bootstrap loader initiates POST (power on
self-test) checks basic system hardware, memory and assigns resources
The startup Bios checks CMOS compares it to
POST checks RAM IS not permanent and may be changed.
BIOS VS CMOS
|
STORE IN ROM
|
STORE IN RAM
|
|
PERMANENT
|
VOLATILE
|
|
CAN NOT BE EDITED
|
CAN BE EDITED
|
System resources
IRQ-I/O-Memory
addresses-DMA
IRQ is the interrupt request and
communication channel from hardware device to CPU, each device has its own
channel. See resource assignments in system information and device manager,
here trouble shoot hardware and resolve resource conflicts.
(IRQ3, COM2,
4), (IRQ4, COM1, 3), (IRQ5, LPT2 or sound card), (IRQ7, LPT1 (Printer))
A conflict occurs when two devices uses the
same IRQ
I/O address
Each hardware device is assigned its own
and respond to an I/O address when the CPU sends instructions to a device it
uses its own address
DMA (direct
memory access)
Has direct communication channel between
devices and system memory it does not requires CPU to access the memory. Sound
card and joy sticks have direct access to DMA.
References
Itt-tech virtual library Siti Sarah Binti, M., Mohamed, H., Mamun, M. d., & Syedul Amin, M. d. (2012). Cmos Downsizing: Present Past and Future. Journal of Applied Sciences Research, 8(8), 4138.
Diference between CMOS and EEPROM http://arstechnica.com/civis/viewtopic.php?f=11&t=912720 (Centurion, 200)
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