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Ron Williams

Business Innovation Through Information Technology

Hardware

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IT Spending

2001

32%

21%17%

13%

14% 3%

Internal Staff

Hardware

Software

Data & VoiceCommunications

External Services

Other

Source: Gartner 2001

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Some of the Costs

HardwareDepreciationMaintenance Electricity & Space

SoftwareCost/DepreciationUpgrades

Internal Staff (Salaries)

OperationsDevelopmentMaintenance

Installation & TestTechnology ScanExternal Services

CommunicationsHardwareServices (Lines)

What About Downtime, Obsolescence, Opportunity Costs?

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Input

• Input: collecting raw data to be processed

• Forms of input include:– Keyboard (most widely used input device)– Pointing devices, such as mouse, trackball, touch pad, touch-

sensitive screen, pen– Scanners, including desktop systems with OCR programs, POS

terminals, MICR– Voice recognition

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Output

• Output: converting computer data into a form usable by humans

• Forms of output include:– screens (monitors)– printers– voice (audio)

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Conceptual View of Processing

CPUCPU

Primary Primary MemoryMemory

Other System ComponentsOther System Components

DataData

Programs Programs (Software)(Software)

Storage

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Central Processing Unit (CPU)

• Two main components that must work with the primary memory in order for processing to occur in the CPU:

(1) control unit, which interprets instructions and manages the sequence of operations, such as sending of data in and out during processing

(2) arithmetic-logic unit, where arithmetic (mathematical) and logical (comparison) operations are actually performed

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Machine Cycle

• Sequence of events for CPU to interpret and execute a program instruction

• Instruction cycle: part of the machine cycle during which an instruction is obtained and interpreted

• Execution cycle: part of the machine cycle during which operations are performed based on results of instruction cycle

• MIPS: millions of instructions per second; used as a computer speed comparison measure for many larger systems

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Microprocessors - Speed Factors

• Clock speed (number of electronic pulses produced each second)

• Word size (number of bits that can be processed at one time)

• Bus width (number of bits that can travel at one time)

• Memory capabilities (how much data and instructions can be available at a time)

• Cache size and type (some cache is closer to the processor and thus has faster access)

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Primary Memory

• Primary memory temporarily stores instructions, data, and results; referred to as “volatile”; contents of memory may be lost if the power goes off

• Contents are replaced by other data brought in to the same location, a write process that is referred to as “destructive”; accessing data but not changing it is a read process, which is “nondestructive”

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RAM versus ROM

• Random-Access Memory (RAM)– Working area for various activities– Temporary holding place for data/programs– Contents retained only when computer is on

• Read-Only Memory (ROM)– Location of startup procedures– Holding place for all permanent internal instructions– Contents retained when computer is on or off

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Differences in Storage Sizes

Gigabyte>1 billion bytes

Megabyte>1 million bytes

Kilobyte>1 thousand bytes

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Magnetic Disk Storage Media

• Disks are direct access storage devices (DASD), because each storage position has a unique address that can be accessed directly instead of limited to the sequential design of magnetic tape media

• Disks have tracks that are subdivided into “sectors”; the tracks and sectors are part of the data’s address used for access

• Two forms of magnetic disk are floppy disks and hard disks

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Floppy Disks

• Most microcomputers today have a 3 1/2” floppy disk drive and may also have a Zip disk drive

• Disk drives have read/write heads (also used with magnetic tape systems), which are on access arms that move over a disk

• Access time: how long it takes for a seek operation (reaching the appropriate track) and a search operation (reaching the appropriate position on the track); then data is transferred to memory

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Hard Disks

• Use of a disk drive with one or more metal disks, usually built into the computer hardware and tightly sealed

• Operates similarly to a floppy disk drive, but hard disk drive can rotate faster

• May include multiple disks arranged as a disk pack, in which disks rotate together with access arms in between disks; a particular track location on all disks is called a cylinder and is used as part of an address of data stored on a disk

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Optical Disk Storage Media

• Uses laser technology

• Has a longer shelf life than magnetic media

• Cost of storage is higher than for magnetic media

• Can be used for permanent storage of data, in which what is stored is never changed, and also for data that can be erased so that the disk can be reused

• Used extensively for storage of images

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“Write-Once” Disks

• WORM technology: acronym for “write once, read many”; data that is stored cannot be erased but can be read as often as desired

• Disk may continue to be used for data storage until it is full, although existing data cannot be changed

• Permanence of storage has allowed data stored in this way to be used as legal evidence and for other permanent records

• CD-ROM is written to only once, usually all at one time, rather than being able to add data later

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Storage Media Comparison

• Magnetic tape– Widely used for backup copies, in which sequential arrangement is

acceptable

• Magnetic disk– Useful for day-to-day activities requiring direct access

• Optical disk– Useful when storage of photos and other images is required– Backup copies as prices decrease

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DBMS

Database

Server

ApplicationProcessing

Distributed computing

Client

Client

Client

Clients & Servers

DesktopApplicationProcessing

Department/Division/Enterprise

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Server (Multi-user)NT (Dell, HP, IBM, Compaq)UNIX (Sun, HP, IBM)OS/400 or MVS (IBM)LINIX (IBM, Dell, Sun, etc)

Operating SystemUNIXNTOS/400OS390LINIX

Distributed computing

Intel Client

Client

Client (Single-user)

Hardware & Operating System are Closely Linked

Windows

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Rapid Decline in Hardware Costs

• Moore’ Law (Semiconductors)– Gordon Moore, co-founder of Intel, observed in 1965 that chip density of integrated

circuits had double every year since invented– Moore’s Law later modified to say that chip density would double every 18 months

• Has proven true• Predicted to hold for at least next 21 decades

– Implication – one gets 2X the computer power for the same price every 18 months – Example

• 1974: Intel 8080 3500 Transistors 8 bit addressing .06 MIPS (Million of Instructions per minute)

• 2000: Intel Pentium IV 25,000,000 Transistors 32 bit addressing > 1500 MIPS

• Storage Costs– 1980 - $1000/megabyte– 1992 - $1/megabyte– 2002 - $1/gigabyte

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Rich-Con Steel Concerns

• Why did Rich-Con keep the hardware so long?

• How did that impact software decisions?

• How did they both impact the business?

• What should they have done over time?

• What should they be concerned about now with regard to hardware and software?