Transcript Concepts Unit B

Unit B – Software,
Files, and Computer
Architecture
Pages B1 – B26
of the
Concepts Book
Software
 Program – a set of instructions that tell the
computer what to do and how to do it
– What language is shown on page B-3?
 Data vs. Information
– Data is basic or raw, unprocessed input (numbers)
– Information is processed or assembled data (chart)
 Software (by the book’s definition) includes
programs (instructions) and associated data
 System Software (machine) vs. Application (user)
Operating Systems
 Software that controls the computer
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Acts as go-between for applications and hardware
External vs. internal services
Performs basic input and output
Allocates and manages all system resources
Allows for multitasking
• Multitasking means the computer can perform more than one
complex operation at one time
• What’s the difference between multitasking and multiuser?
– Detects (causes?) hardware failures
– Maintains security
Device Drivers
 Addition to the operating system
 Incorporates instructions needed for the
computer to communicate with a specific
(type of) device not previously present
 Usually must be installed before and/or
after the device (Plug and Pray?)
 May be prompted to install
 Software may be on disk or CD, or online
Windows
 What company had the rights to the first
windowing system, and what happened?
 Which competitors continued the concept?
 Microsoft Windows 1.0, 2.0, 3.0
 Microsoft Windows 3.11 (networking)
 Microsoft Windows 95, 98, NT, 2000, ME
 Office versions vs. Windows versions
Applications
 Applications perform a specific task or a related
set of tasks
– Productivity word processing, spreadsheet, database
– Suite combination of compatible applications
– Groupware collaboration and revision
– Business software
• Horizontal – wide range of customers (payroll)
• Vertical – specific type of customer, different levels
– Other classifications on B-9
Logical File Storage
 Conceptual way data is stored
 Two common representations
– Filing cabinet or cardboard boxes
– Tree
 Each file has a name +/- an extension
– Extension can tell you the data/file type
– Extension used to determine which program
opens file – “document centricity”
Data Files vs. Executables
 Data files contain words, numbers, pictures,
reports, graphs (information?)
– DAT, DOC, XLS and TXT
 Executable files contain instructions that the
computer executes to perform a task
– EXE, BAT, and COM
– Some executable files can be started by users
(EXE and COM files); other executable files
(DLL, OCX, and VBX files) are started by other
executable programs.
File Name and Directory
Points
 A directory is a discrete portion of a storage
device (folder or branch)
 Root directory is the main list of all files and
subdirectories on a volume
 Each storage device has a device letter (?)
 The file name is a unique combination of a
name +/- an extension
 A complete or qualified filename includes the
full path (list of directories and drive letter)
 Cannot have two files on same device with
same complete file name!!!
File Name Anomalies
 Operating system considerations
 Web considerations
– Forward and backward slashes
– Certain characters cannot or should not
be used in file names
 Wildcards
Physical File Storage
 Storage medium is the substance that
contains the data
 Storage device records and retrieves
data from the medium
 Saving a file is also called storing or
writing a file; retrieving a file is also
called opening or reading a file
Once Bitten . . .
 Data is stored digitally in bits (1s and 0s)
 Kilo = 210 = 1,024 ~1,000
 Mega = 220 = 1,048,576 ~1 million
 Giga = 230 = 1,073,741,824 ~ 1 billion
 Tera = 240 = 1,099,511,627,776 1000 gigabytes
 1 byte = 1 character = 8 digits
 What’s a nybble?
Types of Storage Devices
 Hard Disk
– 20 megabytes to 120 gigabytes
– Used for long-term storage, applications, large files
 Floppy Disk – Figure B-14
– 5 ¼” floppy
– 3 ½” floppy (SD, DD, HD)
– Zip Disk (is this really a “floppy”?)
– Used for distributing, storing, and backing up relatively
small files
Storage Device Speed Factors
 Access time is the average time required to
locate and read a given piece of data
 Access time is measure in ms (milliseconds)
 Random vs. sequential access devices
 Data transfer rate (sort of) indicates the
quantity of data that can be moved in one
second
Magnetic Storage
 Blank media start with randomly-scattered
patterns on magnetic-oxide-covered Mylar
 Read-write head polarizes particles into a
pattern which holds data
 Pattern can be “erased” or “reformatted”
 Double-sided vs. double-density
 Tracks, Sectors and Clusters, oh my!
 Death Knells for Storage
Optical Storage
 Microscopic dark and light spots (“pits” and
“lands”) burned onto the medium
 Is optical storage changeable?
– CD vs. CDR vs. CDRW
 Crystalline innovations
 Molecular innovations
Computer Architecture
 Integrated Circuit – basic component
– Crystal or wafer with embedded wires, transistors, and
resistors
– Encased in ceramic or plastic carrier, usually with pins
– DIP, SIMM, DIMM, PGA (pin grid array, Pentium)
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Motherboard, daughterboards/cards, ports
Power supply
Storage (hard and floppy disks)
Wires, cables, battery, fan, bus, etc.
Memory
 Memory vs. storage
– Memory can be classified as long- or short-term, as can storage
– Text says that memory circuits have a direct link to the
processor, while storage media do not
 CMOS = Complementary Metal-Oxide Semiconductor
 ROM = Read-Only Memory
– Remains after power is off
 RAM = Random Access Memory
– Erased when power is removed
 Memory speed
– Nanosecond = one billionth of a second
– 60 to 80 was norm, now < 8 ns
– SDRAM is a fast type of memory
 What is virtual memory?
The CPU
(Central Processing Unit)
 Performs arithmetic and logic functions and
executes instructions
 RAM sends data and instructions to the CPU,
which returns processed data to RAM
 For a microcomputer (PC), the CPU is called a
microprocessor
 Intel, Cyrix, AMD – are they compatible?
 Pentium heats up the market
 Anyone want some Celeron soup?
Stuff You Just Might Possibly
Have a Chance of Encountering
on a Test Someday
 Issue: Is Data Getting Lost?
 Independent Challenges 3, 4, and 8
 Visual Workshop