overview of computer hardware cs 1 introduction to computers and computer technology rick graziani...

Overview of Computer Hardware

CS 1 Introduction to Computers and Computer Technology

Rick Graziani

Fall 2006

Rick Graziani [email protected] 2

Hardware Components

SYSTEM UNITINPUT OUTPUT

PERMANENTSTORAGE

Know these!


The System Unit

Let’s open the box!


The System Unit

circuit board = a board with integrated circuits (microchips)

• system board or motherboard

• interface boards or expansion boards

system board or motherboard = a single circuit board with the components which make up the computer’s processor for a microcomputer, including the:

• CPU (Central Processing Unit)• Memory

– RAM– ROM or ROM BIOS

• expansion slots


circuit board = a board with integrated circuits (microchips)

• system board or motherboard

• interface boards or expansion boards

The System Unit


system board or motherboard = a single circuit board with the components which make up the computer’s processor for a microcomputer, including the:

• CPU (Central Processing Unit)

• RAM

• ROM or ROM BIOS

• expansion slots

The System Unit


Interface board/card (or Expansion board/card)- used to connect peripheral devices (monitor, printer, etc.) to the motherboard (more on this “later”)

The System Unit


The System Unit


Inserting an Interface card or Expansion board into an expansion slot of the motherboard

The System Unit


The System Unit

• Integrated Circuits (microchips) What can they do?

• 1. Store bits: store the data and instructions used for processing

• Example: RAM and ROM chips (later)

2. Process bits: process the data and instructions

Example: CPU (next)


The CPU- The Real Computer

CPU (Central Processing Unit)= A complex collection of electronic circuits on one or more integrated circuits (chips) which:

1. executes the instructions in a software program

2. communicates with other parts of the computer system, especially RAM

The CPU is the computer!


Some of the parts of the CPU

Arithmetic Logic Unit (ALU) = area of the CPU responsible for the actual processing

“The CPU’s calculator”

Control Unit (CU) = area of the CPU responsible for getting data and instructions from RAM


What is in charge of the CPU?

The operating system software! The “OS”

Windows XP, Macintosh OS, Linux/UNIX, etc.

The operating system manages what programs and data the CPU will be working on.

More Later on Operating Sys.!


A CPU can be:

A CPU can be:

1. A series of integrated circuits (chips) on one or more circuit boards– Older mainframe and minicomputers

2. On a single integrated circuit known as a microprocessor

microprocessor = a CPU on a single chip

microcomputer = older term for a computer with a microprocessor(s) (PC, Macintosh)


The Microprocessor (again)


CompatibilityWhy can’t I run Windows software on my Macintosh and visa versa?

• Operating system software is designed to run on one specific type of CPU or “family of CPUs”

• Application software is designed to work with a specific operating system software, thus one specific type of CPU or “family of CPUs”

More “later”

The Microprocessor


RAM- Primary Memory

RAM (Random Access Memory) = integrated circuits (chips) used to temporarily store software (programs, instructions) and data

• “primary” storage for the CPU

• electronic switches, storing ON’s and OFF’s


RAM – Primary Memory (storage)

Temporarily stores for the CPU:

Software

• operating system software

• application software

Data

• documents, spreadsheets, etc.


RAM


Inserting RAM onto the motherboard


RAM is TEMPORARY memory

RAM is volatile

• stores ON and OFF bits (software and data) electrically

• when power goes off, everything in RAM is lost

RAM - Volatile


Why does the CPU use RAM?

• The CPU is very FAST!

• The CPU needs the instructions (software) and data as quickly as possible

• If the CPU has to wait, so does the user

Why doesn’t the CPU use permanent storage like disk drives?

• Too slow

• EXAMPLE: Spellchecker

RAM - Speed


RAM - Capacity

The amount of RAM determines:

• What software and data the user can work on

• how much software and data the user can work with

“Not enough memory” error message from the Operating System

• The more complex and sophisticated the software, the more instructions that software contains, which means larger software files.


RAM - Capacity


If RAM is temporary where is the data and software stored permanently?

Permanent storage devices such as:

• hard disk drives

• floppy disks

• CD ROM disk

• Flash sticks

(“later”)

RAM – Temporary Storage


Example: Typing a document in Microsoft Works

In RAM memory

• MS (Microsoft) Windows XP operating system or Macintosh OS

• MS Words

• the document

What the user sees on the screen is being stored in RAM


RAM

0

256 MB

Hard Disk Drive

CPU

ROM

Operating System Software

Application Software

User data (information)

“The kernel”

MS Word


ROM - Read Only Memory

ROM (Read Only Memory) = integrated circuits (microchips) that are used to permanently store start-up (boot) instructions and other critical information

Read Only = information which:

• cannot be changed

• cannot be removed

• cannot be appended (added to)


ROM is sometimes known as ROM BIOS (Basic Input Output System software)

ROM permanently contains:

• start-up (boot) instructions

• instructions to do “low level” processing of input and output devices, such as the communications with the keyboard and the monitor



Firmware = software program which is stored permanently on a microchip, such as the software on the ROM chip



Booting up the computer

Booting the computer = starting the computer

Four phase of the boot process: S.P.I.T.

1. System Start-up

2. Power On Self-Test (POST)

3. Initialization

4. Transfer to the operating system software


1. System Start-up

• Turning on the computer

• Power supply supplies electricity to the computer

• The ROM chip boot instructions (firmware) is now “in charge”

• ROM chip instructions processed by the CPU


2. Power On Self-Test

The ROM chip boot instructions tests the “processor” including:

• checks the CPU

• tests RAM memory and calculates it’s capacity

• checks other components on the motherboard


3. InitializationThe ROM chip boot instructions checks the “peripheral devices” including:

Input devices

• keyboard, mouse

Output devices

• monitor, printer

Storage devices

• hard disk

• floppy drives

• CD ROM drive


What is a peripheral device?

A device which is connected to the computer’s processor, including input, output, and storage devices.

(More later)


4. Transfer to an operating system software

• The ROM chip boot instructions are now finished

• The ROM chip wants to give control over to an operating system software

• The ROM chip searches for the operating system (usually on the hard disk drive) and transfers an operating system file (the kernel) into RAM memory


Booted up

The operating system software is now in charge!

• The operating system file, known as the kernel, is in RAM memory

• The user may now access application programs and data (double click on MS Word)

• The operating system software is in charge

(More later)

Inside the CPU


The CPU


CPU

• The CPU is the brains of the computer.

• The CPU is the computer!

• The CPU decision is the most important decision you will need to make in purchasing a computer.

• Operating system software and application software requires a minimum type of CPU (don’t limit yourself in your purchase)


The Operating System Software and the CPU

• OS manages the CPU

• OS manages what the CPU will work on and when

• The user can only take advantage of the complete abilities of the CPU only if the operating system software and application software also have those abilities.


Tighter Circuitry

• Closer the circuits are together, the more circuits that can fit on a single chip

• Faster performance when there are fewer chips

• Moore’s Law: Gordon Moore, chairman of the board of Intel in the 1960’s stated that transistor densities on a single chip would double every 18 months


Power of the CPU

1. The number of bits processed

2. The size of the CPUs data bus

3. The Speed of the CPU

4. Internal Cache



Toll Booth Analogy


Early microprocessors:

• 4 bit and 8 bit processors

• Intel 8088, 80286: 16 bit processors

• Intel 80386, 80486, Pentium: 32 bit processors

• Motorola (Apple) 68020, 30, 40 and the PowerPC: 32 bit processors

Current processors

• 32 bit processors

Latest:

• 64 & 128 bit processors



Pentium III


Pentium 4


AMD Processors (continued)


VIA C3 Processor


64-Bit Processors

• Intel Itaniums

• AMD 64-bit processors


The Itanium 2 Processor


AMD 64-Bit Processors


CPU Heat Sinks and Cooling Fans


Combination Heat Sink and Cooling Fan


• Toll Booth

2. The CPU’s Data Bus


2. The CPU’s Data Bus

Data bus = the number or wires between the CPU and RAM

More wires (lanes) the faster the CPU gets the data and software to process

Older CPUs: 8 and 16 bit data bus

Newer CPUs: 32 and 64 bit data bus


The OS also plays a part!

Amount of RAM recognized by the Operating System

• Windows 95: 1GB

• Windows 98: 1GB

• Windows 98SE: 1GB

• Windows ME: 1.5GB

• Windows NT: 4GB

• Windows 2000 Professional: 4GB

• Windows XP Home: 4GB

• Windows XP Professional: 4GB

• OS X: 8GB due to current hardware limitations

• OS 9.x: 1.5GB (no single application can utilize more than 1GB)

• Linux: 64GB



Speed measured in

• megahertz (MHz) - the number of millions of beats per second

• gigahertz (GHz) - the number of billions of beats per second

Examples:

• Early CPUs: 4 - 33 MHz

• Current Processors: 3 GHz and more

Faster the CPU, faster the processing (Toll Booth)

Cost $$$ and Manufacturing


4. Internal Cache

Internal Cache = memory inside the CPU chip which stores instructions and data which the CPU is currently working on or may soon need.

• The CPU must deliver its data at a very high speed.

• The regular RAM cannot keep up with that speed.

• Therefore, a special RAM type called cache is used as a buffer - temporary storage.

• L1 Cache – Same chip as CPU (fastest)

• L2 Cache – Separate chip


Apple G5

• G5 drives the largest performance gain in the history of the PowerPC.

• The 64-bit G5 offers speeds up to 2.5GHz and can address up to 8GB of main memory.


Intel Duo Processor

• Two CPUs in one.

• Which means it can run at a slower clock speed without sacrificing performance.– Two oxen better than one.

• Less power consumed, runs cooler.

• 4 MB shared L2 cache.

Storage Devices


Permanent Storage

• What is in charge of permanent storage devices?

• The operating system software!

PROCESSORINPUT OUTPUT

PERMANENTSTORAGE


Cost v.s. Speed


Direct Access Devices vs. Sequential Access

Analogy:

• Record/CD vs. Cassette Tape


Sequential Access Devices

Sequential Access = In order to access specific information, the device must sequentially pass through all preceding information

• 9 Track Tape (Reel to Reel)

• Cartridge Tapes


Reel to Reel Tape (9 Track Tape)


Using a Cartridge Tape Drive


Storing Data on Tape


Recording information• Bits are recorded as positive and negative polarity on

magnetic tape (“magnetic media”)

Advantages• inexpensive• durable• portableDisadvantages• slow access rate

Primary UseBacking up “on-line” information

Storing Data on Tape


Direct Access Devices

Direct Access = The specific information is accessed directly

Examples

• floppy disk drives

• hard disk drives

• cartridge disk drives

• CD ROM and DVD drives


Floppy Disks

Floppy Disk = iron oxide coating on a portable mylar plastic disk

Becoming obsolete

Old 5 1/4 inch diskettes (FYI)• double density = 360K capacity• high density = 1.2 MB capacity


Newer 3 1/2 inch diskettes• double density = 720K capacity• high density = 1.4 MB capacity(Right drive for the right densities)

Advantages of 3 1/2 inch• size, capacity, speed, durability

Notch with slide = write protection• closed = Read/Write• open = Read Only

Floppy Disks


• Bits are recorded as positive and negative polarity on magnetic tape (“magnetic media”)

Recording information


• temperature• magnets• touch, smoke, dirt• folding, bending, pressure

Magnetic Media is sensitive to:


Hard Disk Drives

Hard Disk = Iron oxide coating on one or more rigid aluminum disks called platters


Common Sizes

Older Disks

• 5 MB, 10 MB, 20 MB, etc.

Newer Disks

• 50 GB and more!

• Smaller, cheaper and faster!

Advantages of Hard Disk Drives over Floppy Disk Drives

• more capacity

• faster access

Hard Disk Drives


How data is stored on disks

Hotel analogy

• What is in charge of storing information on the hard disk drive (and other storage devices)?

• The operating system software!


track = a series of concentric rings on the disk• A track is divided into several sectors(track) sector =a section of a track which stores a

predetermined number of bytes (bits)



Several sectors are combined to create clusters or blocks

cluster (Windows and Macs) or block (UNIX) = The number of sectors which is allocated on the disk each time a file needs space on the disk.

Windows 95 (later versions) and Windows 98 using FAT32 1 cluster = 8 sectors (4K bytes) Recognizes disk drives up to 2 terabytes (2 trillion bytes)



FAT (File Allocation Table) and Directory = A file, a table, which is found on one of the first sectors of every diskette and hard disk drive (created when the disk is formatted), and contains information regarding every file stored on that disk including the file name, the date and time that file was created or modified, the size of the file, and which sectors are allocated for that file.

ExampleCreating a new file and saving an existing file to disk



Fragmentation and Defragmenting


How data is physically stored on the disk

Read/Write Heads = Part of disk drive which skims the disk (ten millionths of an inch) in order to retrieve or store information.

Disk Crash or Head Crash = When the R/W head touches the disk.


Formatting a disk

Q: Why do we format a disk and what actually does it?

A: We format a disk so it can be used by the operating system software. The operating system software does the formatting of the disk.

Q: How does the operating system do it?

A: There is a operating system software file (program) which does the formatting. (CPU/RAM)


What does formatting a disk do?

1. Erases all of the information on the disk

2. Prepares disk to be used by the operating system software.

• divides tracks into sectors

• determines cluster size

• creates a file allocation table (FAT) or similar table on other operating systems

3. Optional: Copies operating system files to this disk in order to make this a “boot disk”

Formatting a disk


How Data is Removed from Floppy disks and Hard disks

Who's in charge of deleting files?

Deleting a file:

Unerasing a file


Recovering Data

• Norton Utilities™ – Optimizes and

defragments files for faster hard drive performance.

– Detects and fixes many Windows® and disk problems automatically.

– Can monitor your PC continuously to spot problems before they occur.


Optical Disks - CD ROMs

Recording bits of data

• Data is permanently recorded by a laser beam on a disk

• WORM = Write Once Read Many


Pit = OnNo Pit (Land) = Off


Advantages of CD ROM over magnetic disks

• capacity and durability

Disadvantage

• WORM

Read Only Drives and Read/Write CD ROM Drives

Capacity

• currently = 650 MB



What are CD ROMs good for?• graphics, videos, games,

software, (backups)

Speed of CD ROM Drives• 4x, 6x, 8x, 10x, etc.• larger the number, faster the

transfer speed from the CD ROM to RAM

What’s next?• Need more capacity and faster

speeds.



http://www.computerhope.com/help/cdrom.htm

• OTHER CD TECHNOLOGIES

• CD-R - (CD Recordable) Drive which you are able to write to once. Once the drive is written to it cannot be erased.CD-RW - (CD ReWritable) drive which is a popular alternative to the CD-R drive. CD-RW has the capability of being written to at least one thousand times. The drawback with CD-RW diskettes is with the lower reflectivity of the disc itself can limit the readability. Many CD-ROM and CD-R drives may have a difficult time reading these disks.DVD - (Digital Versatile Disc) New standard released in 1995 which originally was called Digital Video Disc was later changed to Digital Versatile Disc. DVD offers an initial storage capacity of 4.7GB (of digital information on a single-sided, single-layer disc the same diameter and thickness of a current CD-ROM. DVD-RAM - ReWritable drive type that uses a phase-change technology like the CD-RW drives. However , DVD-RAM discs cannot be read by standard DVD-ROM drives because of the differences in both reflectivity of the medium and the data format.


http://www.videohelp.com/dvd

• DVD-R and DVD-RW– DVD-R was the first DVD recording format released that was compatible with

standalone DVD Players.– DVD-R is a non-rewriteable format and it is compatible with about 93% of all DVD

Players and most DVD-ROMs. – DVD-RW is a rewriteable format and it is compatible with about 80% of all DVD

Players and most DVD-ROMs. – DVD-R and DVD-RW supports single side 4.37 computer GB* DVDs(called DVD-5)

and double sided 8.75 computer GB* DVDs(called DVD-10).– These formats are supported by DVDForum.

• DVD+R and DVD+RW– DVD+R is a non-rewritable format and it is compatible with about 89% of all DVD

Players and most DVD-ROMs. – DVD+RW is a rewritable format and is compatible with about 79% of all DVD

Players and most DVD-ROMs.– DVD+R and DVD+RW supports single side 4.37 computer GB* DVDs(called DVD-5)

and double side 8.75 computer GB* DVDs(called DVD-10).– These formats are supported by the DVD+RW Alliance.


http://www.videohelp.com/dvd

• DVD+R DL– DVD+R DL or called DVD+R9 is a Dual Layer writeable DVD+R. The dual layered

discs can hold 7.95 computer GB* (called DVD-9) and dual layered double sides 15.9* computer GB (called dvd-18).

• DVD-R DL– DVD-R DL or called DVD-R9 is a Dual Layer writeable DVD-R. The dual layered

discs can hold 7.95 computer GB* (called DVD-9) and dual layered double sides 15.9* computer GB (called dvd-18).

• DVD-RAM

• DVD-RAM has the best recording features but it is not compatible with most DVD-ROM drives and DVD-Video players. Think more of it as a removable hard disk. DVD-RAM is usually used in some DVD Recorders.

• This format is supported by DVDForum.


• Over 2 hours of high-quality digital video (over 8 on a double-sided, dual-layer disc).

• Support for widescreen movies and standard or widescreen TVs (4:3 and 16:9 aspect ratios).

• Up to 8 tracks of digital audio (for multiple languages), each with up to 8 channels.

• Up to 32 subtitle/karaoke tracks. • Multilingual identifying text for title name, album name, song name, actors,

etc. • Automatic "seamless" branching of video (for multiple story lines or ratings on

one disc). • Up to 9 camera angles (different viewpoints can be selected during playback). • Menus and simple interactive features (for games, quizzes, etc.). • "Instant" rewind and fast forward, including search to title, chapter, track, and

timecode. • Durability (no wear from playing, only from physical damage). • Not susceptible to magnetic fields. Resistant to heat. • Compact size (easy to handle and store, players can be portable).

What are the features of DVD-Video?


Disk Cartridges

Disk Cartridges = portable disks which store almost as much information and is almost as fast as a hard disk drive

Uses

• same as floppy or tape

Examples:

Iomega Zip Drive = 100 MB

Iomega Jaz Drive = 1 GB


Flash Drives

• Capacity– 64 MB– 128 MB– 256 MB– 512 MB– 1 GB– And more

• $35 to $175

Overview of Computer Hardware

CS 1 Introduction to Computers and Computer Technology

Rick Graziani

Fall 2006

overview of computer hardware cs 1 introduction to computers and computer technology rick graziani...

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