COMPUTER ORGANIZATION ANGELITO I. CUNANAN JR.

MEMORY MANAGEMENT  In multiuser, multitasking or multiprogramming system, memory must be specifically managed to handle multiple programs.  Physical size of main memory is usually not large enough to accommodate the operating system and all of the application programs which are need to execute the programs by users.

MEMORY MANAGEMENT How Memory management work?  Can be provided by an Operating System or with the help of MMU (memory, management unit).

MEMORY APPS rapsa! ajejeje

MEMORY MANAGEMENT Uniprogramming system  Main memory is partitioned in two portions: OS and program that is currently executed.

MEMORY MANAGEMENT  Modern MMU provides virtual memory to handle large program or large number of programs.  And this is achieved by using swapping technique.

MEMORY DEVICES 3 Types of memories from technology point of view:  Semiconductor memory  Magnetic memory  Optical memory

SEMICONDUCTOR MEMORY  Static, faster, lighter, smaller in size and consume less power. 2 types of semiconductor memory  RAM (Random Access Memory)  ROM (Read Only Memory)

SEMICONDUCTOR MEMORY RAM (Random Access Memory)  Read/write memory  Information can be read and written into and read from RAM  Volatile memory  When power supply goes off the stored information in RAM is lost

RAM WHERE IS RAM?

SEMICONDUCTOR MEMORY ROM (Read Only Memory)  Permanent type of memory  Its contents are not lost when power supply goes off.  User cannot write into ROM  Its contents are decided by the manufacturer and written at the time of manufacture.

ROM WHAT THE…!!!

SEMICONDUCTOR MEMORY 2 types of Programmable ROM (PROM) 1. Erasable PROM 2. Electrically erasable PROM  User can write information in PROM  Flash Memory, similar to EEPROM but has higher packing density, lower cost and greater reliability.

MAGNETIC MEMORY  Non-volatile memory  Store information permanently  Slower than semiconductor  Bulk storage devices 2 types of commonly used magnetic memory 1. Hard disk 2. Tapes

MAGNETIC MEMORY Hard disks  Made of aluminium or other metal or metal alloy which are coated on both sides with magnetic material usually iron oxide.  Not removable from computer

MAGNETIC MEMORY Hard disks  To increase the storing capacity of hard disk, several disk are packed together and mounted on a common drive to form a disk pack.  Disk is also known as platter.  Disk packed into sealed container is called Winchester disk drive.

MAGNETIC MEMORY Hard disks  When the Disk is packed into sealed container, dust-free, and allow very high speed usually 7200rpm-15000rpm (revolution per minute)  Data transfer rate is MBps  Average access time is about 5-10 sec.  2.5 inch and 3.5 inch diameter

MAGNETIC MEMORY Hard disks  Storing capacity per disk is up to 1000GB.  Storing capacity of hard disk drive unit is up to 4TB. (HDDU contains more than 1 platter)

MAGNETIC MEMORY Hard disks controllers  Used to interface hard disk and processor.  Intel types of hard disk controller 1. IDE (integrated drive electronics) 2. SCSI (small computer system interface) Adapters SATA – Serial Advanced Technology Attachment (3GBps)

MAGNETIC MEMORY Magnetic Tape  medium for magnetic recording  made of a thin magnetisable coating on a long, narrow strip of plastic film  developed in Germany  Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders.

MAGNETIC MEMORY Magnetic Tape  Mass storage device  Used for backup storage

MAGNETIC MEMORY Optical memory  Information is written to or write from an optical disk or tape using laser beam.  Very high storage capacity Types of optical memory 1. CD-ROM 2. CD-R 3. CD-RW 4. DVD-ROM 5. DVD-R 6. DVD-RW

BURN + KNEE =

MAGNETIC MEMORY  Disk size is 5.25 inch diameter  CD-ROM (80ms, 4800KBps)  CD-RW (700MB capacity)  DVD-ROM (4.7 GB-50GB)