computer performance & storage devices computer technology
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Boot Process
Sequence of events that occurs between the time you turn on a computer and the time that it becomes ready to accept commands.Purposes
• Runs a diagnostic test to make sure everything is working.
• Loading the operating system, so the computer can carry out basic operations.
6 events of the boot process:
Power up Start boot program Power-on self-test Identify peripheral devices Load operation system Check configuration and
customization
Circuits
The path from one component of a computer to another that data uses to travel.
Circuits run between RAM and the
microprocessor RAM and various
storage devices
Megahertz (mHz)
A measurement used to describe the speed of the system clock.
A megahertz is equal to one million cycles (or pulses) per second.
1.3 GHz means that the microprocessor’s clock operates at a speed of 1.3 BILLION cycles per second.
Pentium
Name of the CPU. Pentium is the 5th
generation of the Intel processor. Other generations
were called• 80-88• 286• 386• 486
RAM vs. ROM
RAM “Random Access
Memory” The ability of a storage
device to go directly to a specific storage location without having to search sequentially from a beginning location.
Very volatile• Cannot hold data when
the power is off.• Looses all data when
power is lost.
ROM “Read only memory” Drives can read data
from disks, but cannot store new data on them.
One or more integrated circuits that contain permanent instructions that the computer uses during the boot process.
Binary Number System
A method for representing letters or numbers using only two digits, 0 and 1. Bit
• Each 0 or 1 Byte
• 8 bits
Also referred to as Base 2 Binary Code.
Memory Measurements
Bit Each 0 or 1
Byte 8 bits
Kilobyte Approximately 1,000 bytes Exactly 1,024 bytes
Megabyte Approximately 1 million
bytes Exactly 1,048,576 bytes
Gigabyte Approximately 1 billion
bytes Terabyte
Approximately 1 trillion bytes
Storage Devices
Used to keep data when the power to the computer is turned off.
Medium/media Location where data is stored.
Hard Disk
Usually mounted inside the computer’s system unit.
Can store billions of characters of data. Stated in forms of
bytes:• Megabytes or
Gigabytes
Magnetic Storage
Recording of data onto disks or tape by magnetizing particles of an oxide based surface coating.
A fairly permanent type of storage that can be modified.
Floppy Disk
Round piece of flexible Mylar plastic covered with a thin layer of magnetic oxide and sealed inside a protective covering.
May be referred to as a “floppy”
3½ disk capacity is 1.44 MB or 1,440,000 bytes
Floppy Disk Options
FormattedPreparing the disk for use by the
computer. Write-protected
Setting the disk so that it can not be written to by the computer.
Digital Audio Tape
Method of storing large amounts of data on tape using helical scan technology to write data at high densities across the tape at an angle.
Optical Storage
Means of recording data as light and dark spots on CD or DVD.
Reading is done through a low-power laser light.Pits
• Dark spots
Lands• Lighter, non-spotted surface areas
CD-ROM
“CD – Read Only Memory” Also called CD-R
CD-Read Storage device that uses
laser technology to read data that is permanently stored on compact disks, cannot be used to write data to a disk.
CD-RW
“CD-Read Write” A storage device that reads data from CD’s and also
can write data to CD’s. Similar to a CD-ROM, but has the ability to write to
CD.