GERARDO ZUNIGA
NT1110 CLASS CHAPTER 6
HARD DRIVES the most
important storage device use by any personal computer. The hard disk drive the
operating system (windows, Linux, others..) made of Aluminum or Glass double
sided platters, these are coated with a durable magnetic surface that is divided into sectors (tracks)each
sectors contains 512 bytes of storage along with information about where the
sector is located.
Capacity's range up to 1TB
Most common types of hard disks interfaces in current pc's are serial(SATA) and
parallel (PATA).
PATA is also known as
ATA/IDE. Both of these can also be use by optical drives (CD'S and DVD's) DVD
standard size is 4.8GB.
Two common interfaces that
are used to connect CD-ROMS and DVD-ROMs are the ATA & IDE.
ATA-5 TRANSMITS AT 66MB/s
ATA-6 TRANSMITS AT 100MB/s
ATA-7 TRANSMITS AT 133MB/s
ATA-8TRANSMITS AT 300MB/s
When installing a new hard
drive and your CPU does not recognize the HD you would have to flush the BIOS
so it can take a larger number of addresses.
Floppy drives are absolute now
it has been replaced by the flash drive cd drives and DVD drives.
Fire wire IEEE 1394 has
almost replaced the SCUSI interfaces because it is faster and installs easily
also uses a ISOCHRONOUS DATA TRANSMISION that means it does not need to be synchronized
with clock and processor these feature is very useful for steaming video a
higher speeds at about 3.2GB/SC
MEMORY
RAM, DRAM, SRAM, SDRAM, DDR SDRAM, DDR2 SDRAM, RAMBUS
RAM is
use by programs and data and by the operating system installing more RAM
improves transfers between the CPU and both the RAM & DISK DRIVES.
RAM loses
its contents as soon as you shut down the computer.
Magnetic RAM on the other
hand can hold data for years.
SPEED
3ways: in nanoseconds
Chips on the module (60ns)
Clock speed od data bus
(PC-133 is 133 HZ; pc800 IS 800MHZ)
The throughput (in MBps) of
the memory PC 2,700MBps or 2.7 GBps)
(ECC)
ERROR CHECKING (parity or none-parity) most systems don’t
perform parity checking (to verify the contents of memory) or correct errors
but some mobos support this functions.
DRAM
(Dynamic RAM) requires frequent recharges of memory to retain its contents.
SRAM
(STATIC RAMDOM ACCES MEMORY) does not need to be periodically
refreshed. But is also more bulky and more expensive than DRAM.
SDRAM
(Synchronous Dynamic) was the first type of memory to run in sync
with the processor (the memory Bus). It has 168 pins.
DDR
SDRAM (Double Data rate) performs two transfers per clock
cycle.
DDR2
SDRAM (Double Data Rate) 2, runs its external data bus at twice
the speed of DDR SDRAM or (two transfers /clock cycle) x2.
RAMBUS
(older type memory module) NO LONGER USE. It also must be install
in pairs.
