Computing and the Web Computer Hardware Components

Overview n Basic Concepts of Computer Hardware n Input Devices n Output Devices n Connecting Devices n Primary memory n The Central Processing Unit n Moving information within the computer n Categories of computers n Software applications: Tools for maintaining your PC

Basic Concepts of Computer Hardware n The need to compute

Basic Concepts of Computer Hardware n The need to order information

Basic Concepts of Computer Hardware n The ability to store information

Basic Concepts of Computer Hardware n... And interface with humanity

Basic Concepts of Computer Hardware n Analog Computers....

Basic Concepts of Computer Hardware n Digital Computers...

Basic Concepts of Computer Hardware n Super Computers...

Basic Concepts of Computer Hardware n von Neumann Computer –Program & data are stored in the same memory –Single program counter – one instruction at a time Input devices accept data and programs from the outside world Input devices accept data and programs from the outside world Output devices provide results to the user Output devices provide results to the user Some devices are both input and output Some devices are both input and output

Basic Concepts of Computer Hardware n Input devices –Keyboard –Mouse –Touch pad –Touch screen –Light pen –Microphone –Scanner –Digital camera

Basic Concepts of Computer Hardware n Output devices –Display Monitor –Hard drive –Speakers –Optical Disk –Printers

Basic Concepts of Computer Hardware n Dual Mode (input & output) –Touch screen display –Hard drive –Optical Disk –Network card –Modem –Zip / Jazz drive

Connecting Devices n Direct interface to motherboard –Usually a “card” (NIC, Modem, Special Function) –Usually require special software (driver) n Connect via a “port” –Port is a pathway for data to go in & out of the computer from external devices –External devices are usually referred to as a “peripheral” –Different types of ports have different characteristics

Connecting Devices n Some of the ports: –Parallel –Serial –Video –USB –RJ-11 –RJ-45

Connecting Devices n Properties of ports –Serial vs Parallel –Daisy chain devices (USB or SCSI) –Speed (10M / 100M / 1G) –Buffer requirements / capacity

Storing Data & Information n Three different types of storage: –Primary memory (RAM) –Secondary storage (Hard drive) –Tertiary storage (removable material ie CD) n All storage has characteristics (properties) –Size –Speed –Access method –Volatility

Storing Data & Information n Primary Storage usually called RAM –Random access memory –Electronic (no moving parts) –Fastest type of storage n Access time in the nanosecond range –Direct access (can go directly to any location) –Volatile form of storage –Most expensive of the three types –Special types of memory n ROM (read only memory) n Cache (high speed memory) n PROM (programmable read only memory)

Storing Data & Information n Secondary Storage usually hard drive –Supports direct access at block / file level –Electronic & mechanical ( moving parts) –Slower than RAM due to mechanical aspects n Access time in the millisecond range –Nonvolatile form of storage –Much less expensive than RAM –Usually significantly larger than RAM

Storing Data & Information n Tertiary Storage usually removable –More often than not it is sequential –Electronic & mechanical ( moving parts) –Slower than hard drive due to mechanical aspects and removable media –Nonvolatile form of storage –Cheapest form of storage –Used for archival storage, not frequently referenced, or extremely large data sets n Good for backup purposes

Storing Data & Information n Capacity –1 byte = 8 bits –1K = 1024 bytes –1M = 1024 K = 1,048,576 bytes –1G = 1024 M = 1,073,741,824 bytes –1T = 1024 G = 1,099,511,627,776 bytes n Speed –Millisecond = one thousandth of a second –Microsecond = one millionth of a second; one thousandth of a millisecond –Nanosecond = one billionth of a second; one thousandth of a microsecond

Storing Data & Information n Information Retrieval –Random Access (direct) – allows immediate access to stored data n RAM / ROM (each location is directly accessible) –Sequential Access – requires accessing everything from the beginning of the file up to the item you want n VHS video tape –Pseudo-direct access – can jump to designated starting points n Audio CD – can directly access starting point of each song, but must search within the song sequentially n Type of retrieval and frequency of use will determine how the data should be stored

Storing Data & Information n Characteristics of different types of storage n RAM –Access time: access times ranging from 80ns to 50ns –Size: PCs today can range from 256M to 1G –Cost: depends on density 256M ~ $110 / 1G ~ $375 n Hard drive –Access time: depends on speed – 7200rpm ms –Size: 160 G –Cost: $110 n Removable Storage (Zip / Jazz) [250 M Zip] –Access time: depends on interface – 40ms seek / 1.4Mbps xfer –Size: Unlimited –Cost: $130 + cost of media (8 pack - $85)

The Central Processing Unit n Multiple components within the CPU n ALU : does arithmetic and logic n Control : manages all components n Registers : used to manipulate data n Instruction Decode : figures out what the instruction does n Program Counter : keeps track of next instruction n Accumulator : special register for arithmetic n Buses : interconnect components

Moving information within the computer n Data bus – used to move data between components n Address Bus – used to specify memory location n Control Bus – used to synchronize / regulate components n Data is moved around in bytes n Data moves either serially or in parallel –Serial data is sent one bit at a time ins sequence –Parallel data is sent eight or more bits at a time n Maximum size depends on width of the bus n Pentium has a 32bit data bus n The type of component determines the need for serial or parallel –Keyboard & mouse are serial –Hard drive, CDrom, & Printer are parallel –Everything in CPU is parallel

The CPU Cycle

n Fetch instructions from memory n Decode instructions and fetch operands n Execute the decoded instruction n Service device interrupts n Repeat cycle n Cycle runs at the approximate clock speed of the CPU (more or less)

Categories of computers n Supercomputers – ultimate in speed due to multiple instruction execution n Mainframe – business class computing n Minicomputers – multi-user system n Workstations – single user system n Microcomputers – contains microprocessor n Palmtop Computers – between palm & micro n Calculators – limited functionality

Tools for maintaining your PC n Standard Windows tools –Defragmentation tool –Scan disk for error checking –System Info n 3 rd party tools –Norton disk doctor –System Mechanic

Relationship between Components n Run Task Manager –Examine I/O & Memory parameters n Run msinfo –See what is taking up memory n Run Defrag –See what disk utilization looks like n Performance & Tuning aspects of Computers