Chapter 4 hardware and software
Why do you need to know about information technology?
Information technology
Y2K (year 2000) problem
Resulting of expensive computer memory in the early days of computing
Two-digit to store year values
Knowing something about where technology has been, can help us understand where
technology is headed.
Where did all this information technology stuff come from?
Early computers:
1939 – 1952
Complex and expensive
Single user
One program at a time
Housed at university
1947, EniacMark I
1952, Ferut at U of T
mainframes 主机: 1952 – present
First digital computers
Used in business and government
First generation, were based on now obsolete 过时的 vacuum tubes 真空管
technology
IBM 650 ($200,000 -- $400,000)
Add or subtract 16,000 numbers/second
Second generation mainframes introduced in the late 1950s used transistors 晶体管
Smaller, easier to maintain, reliable
These first and second generation machines were often sold without software:
the assumption was that companies themselves would develop the programs
they wanted to use on the computer.
The third generation of mainframe machines introduced in the mid-1960s including
operating systems and multiprocessing.
Timesharing – many users could share the main processor at the same time.
Cost millions dollars
Mini-computers
Models such as the IBM Z96 still being used today
Fast processing, massive 大量的 storage
Microcomputers: 1975 – present
The first microcomputers, like the MITS Altair 8800 and Datapoint 2200, were
developed in 1975.
These early microcomputers often had no display careen 显示小宗 or monitor
and required users to develop their own programs.
By 1981, the microcomputers had developed enough for companies such as:
IBM, Apple, Compaq, and Texas Instruments to launch the personal computer
(PC)
These microcomputers had monitors 显示器, integrated circuits 集成电路,
key-board, portable floppy disks 便携式软盘, word processors 文字处理器,
spreadsheets 电子表格, and other software.
Networking personal computers: 1985 – present
Local Area Networks (LANs)
Linking many PCs together
Shared access to data, printers and peripheral devices
Gave each computer a specific address and then was able to deliver requests for
data to appropriate addresses.
Wide Area Networks (WANs)
The internet
Email
Web browsing Technology lessons
Technology advances
Moore’s law
Take advantage of the changes
Small is powerful
Use it anyway
Networking is the thing
Communication and collaboration
What does a manager need to know about computer hardware?
Hardware consists of electronic components and related gadgetry that input, process,
output, and store data according to instructions encoded in computer programs or
software.
Central processing unit (CPU)
“Brains” of the computer
Speed (MHz)
Fast CPU needed for:
Complicated calculations and manipulations
Processing large graphics files
Special function cards
Augment basic capabilities 加强基本性能
Sound card
Provides better sound quality
Video card
Enhances clarity and speed of video display
Main memory
Size (MB, GB)
Speed
Increased amount of memory allows for many applications to be run at the same time
Hard drive 硬盘驱动器(magnetic disks 磁盘)
Provide long-term storage
Storage Capacity (size)
Affects performance
Data recorded in concentric circles 同心圆
Disks spin 磁盘旋转 and read/write heads move in/out
Time required to read data depends on:
Rotational delay
Seek time
Optical disks 光盘
Types
CDs
DVDs
Data stored differently
Different capacities and speed
ROM = read-only memory
R = record data once
RW = rewritable
Video displays
Two types
CRTs (Cathode ray tubes 阴极射线管)
Big and bulky 笨重
LCDs (Liquid crystal display 液晶显示器)
Slimmer
Specifications 产品规格
Screen 屏幕 size (in inches 英寸)
Resolution 分辨率 (in pixels 像素)
Pixels 像素 Single point on screen
Number of pixels depends
Size of monitor and creation of image
Resolutions
640 x 480, 800 x 600, 1024 x 768, 1280 x 1024... 1680 x 1050, 1920 x 1080
Optimal grid 最佳网格 for sharpness 锐度 and clarity 清晰度
Input, processing, output, and storage hardware
Input hardware devices 设备 include the keyboard, mouse, document scanners, and
barcode条码 (universal product code) scanners like those used in grocery stores杂货
店.
Processing devices include the central processing unit (CPU), which is sometimes
called the “brain” the computer.
The CPU selects instructions, processes them, performs arithmetic and logical
comparisons, and stores results of operations in memory.
Output hardware consists of video displays, printers, audio speakers, overhead
projects, and any other special-purpose devices.
Storage hardware saves data and programs.
Computer data
Binary digits
Computers represent data using binary digits, called bits.
A bit is either a zero or a one.
Sizing computer data
Bits are grouped into 8-bit chunks called bytes 字节.
Specifications for size of memory
K – kilobytes, 1024 bytes
MB – megabyte, 1024k bytes
GB – gigabyte, 1024MB bytes
TB – terabyte, 1024 GB
In 293 Words, how does a computer work?
The CPU is the major actor. To run a program, CPU must
First transfer the program or data from disk 磁盘 to main memory.
Then, to execute an instruction 执行一个指令, it moves the instruction
form main memory into the CPU via 经由 the data channel 通道 or bus
总线.
The CPU has a small amount of very fast memory called a cache 高速缓存.
The computer main memory contains program instructions for Excel, Acrobat,
and even a browser. It also contains instructions for the operating system (OS),
which is a program has controls the computer’s resources as well as a block of
data 数据块.
If there is not enough memory, it will remove something, perhaps the block of
memory labeled More Excel, and then it will place the just-requested program or data into the vacated space 腾出的空间. This process is called memory
swapping 内存交换.
Why should a manager care how a computer works?
The cache
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