PERFORMING MENSURATION AND CALCULATION

PRIMARY STOAGE OR MEMORY

THIS IS COMPUTER'S MAIN MEMORY, WHICH CONSIST RANDOM ACCES MEMORY (RAM), AND READ ONLY MEMORY (ROM) THAT IS DIRECTLY ACCESSIBLE TO CENTRAL PROCESSING YUNIT.

CPU (CENTRAL PROCESSING UNIT)

THE CENTRAL PROCESSING UNIT (CPU) IS THEPRIMARY COMPONENT OF A COMPUTER THAT ACTS AS ITS “CONTROL CENTER.” THE CPU, ALSO REFERRED TO AS THE “CENTRAL” OR “MAIN” PROCESSOR, IS A COMPLEX SET OF ELECTRONIC CIRCUITRIES THAT RUNS THE MACHINE'S OPERATINGSYSTEM AND APPS.

ROM (READ ONLY MEMORY)

THIS IS THE PORTION OF THE COMPUTER'S PRIMARY STORAGE THAT DOES NOT LOSE ITS CONTENTS WHEN SWITCH OF THE POWER. ROM CONTAINS ESSENTIAL SYSTEM PROGRAMS THAT NEITHER YOU NOR COMPUTER CAN ERASE.

RAM (RANDOM ACCESS MEMORY)

THIS IS COMPUTER'S PRIMARY WORKING MEMORY, IN WHICH PROGRAM INSTRUCTIONS AND DATA ARE STORED SO THAT THEY CAN BE ACCESSED DIRECTLY BY THE CPU VIA THE PROCESSOR'S HIGH SPEED EXTERNAL DATA BUS. RAM OFTEN IS CALLED READ/WRITE MEMORY TO DISTINGUISH IT FROM READ ONLY MEMORY (ROM), THE OTHER COMPONENT OF A PERSONAL COMPUTER'S PRIMARY STORAGE.

DDR (DOUBLE DATA RATE)

DOUBLE DATA RATE (DDR) TECHNOLOGY DOUBLES THE MAXIMUM BANDWITCH OF SDRAM (SYNCHRONUS DYNAMIC RANDOM ACCESS MEMORY). DDR2 OFFERS FASTER PERFORMANCE WHILE USING LESS ENERGY. DDR3 OPERATES AT EVEN HIGHER SPEEDS THAN DDR2; HOWEVER, NONE OF THESE DDR TECHNOLOGIES ARE BACKWARD OR FORWARD COMPATIBLE.

SECONDARY STORAGE

THIS IS A STABLE STORAGE MEDIUM, SUCH AS A DISK DRIVE THAT STORE PROGRAM INSTRUCTIONS AND DATA EVEN AFTER YOU SWITCH THE POWER OFF.

FLOPPY DRIVE

THIS IS REMOVABLE AND WIDELY USED DATA STORAGE MEDIUM THAT USES A MAGNETICALLY COATED, FLEXIBLE DISK ENCLOSED IN A PLASTIC ENVELOP OR CASE. POPULAR IN THE 90'S, THIS WAS EVETUALLY SUPERCEDED BY EXTERNAL FLASH DRIVES IN THE BEGGINING OF 2000'S.

HARD DRIVE/DISK

THIS IS A SECONDARY STORAGE MEDIUM THAT USES SEVERAL RIGID DISKS COATED WITH A MAGNETICALLY SENSITIVE MATERIAL AND HOUSED, TOGETHER WITH THE RECORDING HEADS, IN A SEALED MECHANISM.

OPTICAL DRIVE/DISK

THIS IS A LARGE CAPACITY DATA STORAGE MEDIUM FOR COMPUTERS ON WHICH INFORMATION IS STORED AT EXTREMELY HIGH DENSITY IN THE FORM OF TINY PITS. THE PRESENCE OR ABSENCE OF PITS IS READ BY A TIGHTLY FOCUSED LASER BEAM.

EXTERNAL FLASHDRIVE

THIS IS A SMALL PORTABLE FLASH MEMORY CARD THAT IS PLUGGED INTO A COMPUTER VIA USB PORT AND FUNCTIONS AS A PORTABLE HARD DRIVE BUT WITH LESS STORAGE CAPACITY. THEY ARE EASY TO USE SINCE THEY ARE SMALL AND CAN BE USED WITH ANY COMPUTER WITH USB DRIVE.

VIDEO CARD

IT IS ALSO KNOWN AS THE GRAPHICS ACCELERATOR BOARD. IT IS A VIDEO ADAPTER THAT INCLUDES A GRAPHICS COPROCESSOR AND ALL THE OTHER CIRCUITRY NORMALLY FOUND ON A VIDEO ADAPTER.

COMPACT DISK (CD)

THIS IS A PLASTIC DISK, 4.75 INCHES IN DIAMETER THAT USES OPTICAL STORAGETECHNIQUES TO STORE UP TO 72 MINUTES OF MUSIC OR 650M OF DIGITALLY ENCODED COMPUTER DATA. THE COMPUTER CAN READ INFORMATION IN THE DISK, BUT YOU CAN'T CHANGE THIS INFORMATION OR WRITE NEW INFORMATION IN THE DISK.

CD - R

THIS A RECORDABLE CD-ROM. CD-R TECHNOLOGY IS USEFUL TO LAW OFFICE AND OTHER BUSINESS THAT MUST PERMANENTLY ARCHIVE LARGE AMOUNTS OF INFORMATION, AND IT ENABLES INDIVIDUALS TO MANUFACTURE SEALABLE CD-ROM'S. UNLIKE MOST OTHER STORAGE MEDIA , CD-R DISK CAN BE RECORDED UPON ONLY ONCE.

EXTERNAL HARD DISK

THIS IS A HARD DISK EQUIPPED WITH ITS OWN CASE, CABLES, AND POWER SUPPLY. EXTERNAL HARD DISKS USUALLY COST MORE THAN INTERNAL HARD DISKS OF COMPARABLE SPEED AND CAPACITY.

FILE DIRECTORIES

THIS IS THE INDEX OF THE FILES STORED ON A DISK OR ON THE PORTION OF THE DISK. THE CONTENTS OF A DISK ARE NOT OBVIOUS TO THE EYE. THE OPERATING SYSTEM KEEPS AN UP-TO DATE RECORD OF THE FILES STORED ON THE DISK, WITH SAMPLE INFO0RMATION ABOUT THE FILE'S CONTENT, TIME OF CREATION, AND SIZE.

CUTTENT DIRECTORY

This is synonymous to default directory. This is the directory that an application program uses by default to store and

retrieve files. The current directory is usually determined by the application program defaults and is often the directory in which the program files are saved.

SUBDIRECTORY

This is a directory created in another directory that contains files and additional subdirectories. When a hard disk is formatted, a fixed-size root directory area is created that is only large enough to contain the information for 512MB files. TO add more file to the hard drive, you create subdirectories in which you can store other files.

CALCULATING DATA STORAGE

WHILE A BIT IS THE SMALLEST REPRESENTATION OF DATA, THE MOST BASIC UNIT OF DIGITAL STORAGE IS THE BYTE. A BYTE IS 8 BITS AND IS THE SMALLEST UNIT OF MEASURE (UOM) USED TO REPRESENT DATA STORAGE CAPACITY. WHEN REFERRING TO STORAGE SPACE, WE USE THE TERMS BYTES, KILOBYTES, MEGABYTES, GIGABYTES, AND TERABYTES. CALCULATING DATA STORAGE BITS ARE THE SMAL LEST UNITS OF DATA IN A COMPUTER. THEY CONSISTS OF 8 ONES AND ZEROES.

FOR EXAMPLE: 10011010

IT TAKES 8 BITS TO FORM A BYTE, 1024 BYTES TO FORM A KILOBYTE, 1024 KILOBYTES TO FORM A MEGABYTE, AND 1024 MEGABYTES TO FORM A GIGABYTE.

SYMBOL AND TOTAL NUMBERS OF BYTES

TERMS SYMBOLS BYTES

B Y T E S B

K I L O B Y T E S KB 1 KB =1, 0 2 4

M E G A B Y T E S MB 1 MB =1, 0 4 8, 5 7 6

G I G A B Y T E S GB 1 GB =1, 0 7 3, 7 4 1, 8 2 4

T E R A B Y T E S TB 1TB = 1. 009. 511, 627, 776

CONVERTING BITS TO BYTES

TO CONVERT BITS TO BYTES, YOU SHOULD DIVIDE IT BY 8

CONVERT MEGABYTES INTO KILOBYTES

CONVERTING MEGABYTES INTO KILOBYTES TO CONVERT MEGABYTES TO KI LOBYTES, YOU SHOULD MULTIPLY BY 1000.

ALWAYS REMEMBER!

WHEN YOU ARE CALCULATING FROM A HIGHER SCALE OF DATA TO A LOWER SCALE OF DATA LIKE GIGABYTES TO MEGABYTES, MAKE SURE THAT YOU ARE MULTIPLYING AND IF YOU ARE CONVERTING A LOWER SCALE TO A HIGHER SCALE, THIS TIME YOU DIVIDE