Computer Hardware Principles

Principles of Computer Hardware

• Assembling computer hardware requires understanding each device's role in supporting information systems and organizational needs.
• Computer hardware objectives are subordinate to, but supportive of, information systems and organizational needs.
• Hardware device choices should allow for later improvements.

Reasons to Learn About Hardware

• Hardware improves worker productivity and increases revenue.
• Cost are reduced through better customer service
• Speed-up-time-to-market can be achieved
• Collaboration is enabled among employees and business partners, like suppliers.

Hardware for Processing

• Each computer processes input through a processing unit and primary storage.
• Key components include CPU (Central Processing Unit), ALU (Arithmetic Logic Unit), Control Unit, and Registers

Central Processing Unit

• It is made up of three associated elements - the arithmetic/logic unit (ALU), control unit, and registers.
• ALU handles math calculations and makes logical comparisons.
• Control unit accesses program instructions, decodes them, and coordinates data flow in and out of the Arithmetic Logic Unit, registers, primary and secondary storage, and output devices.
• Registers are high-speed storage areas that temporarily hold the small units of program instructions and data used immediately before, during, and after the CPU executes them.

Processing and Memory Devices

• Machine Cycle Time is measured in nanoseconds (one-billionth of a second), or picoseconds (one trillionth of a second).
• Machine Cycle Time is measured by instructions executed; MIPS (Millions of Instructions per second).
• Clock Speed is measured in megahertz (millions of cycles per second) or gigahertz (billions of cycles per second).
• The faster the clock speed, the more heat generated.

Primary Storage

• Main memory provides the CPU with a working storage area for program instructions and data.
• The main feature of main memory is that it rapidly provides data and instructions to the CPU
• Main memory devices have circuits imprinted on a silicon chip, conducting electricity (on) or not (off), known as binary digits, or bits.
• Data is stored in memory as a combination of on or off circuit states; each character is represented by 8 bits.

Secondary Storage

• The amount of data companies store digitally increases at almost 100 percent yearly.
• Secondary storage, or permanent storage, allows the storing of large amounts of data and instructions more permanently than main memory.
• Compared with main memory, secondary storage offers non-volatility, greater capacity, and economy.

Secondary Storage Devices

• Magnetic tape is a sequential storage medium.
• Magnetic disk is a direct access storage device.
• RAID (redundant array of independent/inexpensive disks) is a method of storing data that generates extra bits.
• Disc Mirror stores data that provides an exact copy
• Virtual tape is used for less frequently accessed data.
• Optical discs uses special lasers to read and write data and provide digital versatile disc-DVD options.
• Holographic disc uses lasers to store computer-generated data in three dimensions and provide holographic storage.
• SSD (Solid State Secondary Storage Devices) stores data in memory chips.
• Memory cards includes flash memory.
• USB (Universal serial Bus) are used
• Computer storage units include Bytes(1), Kilobytes(1024), Megabytes(million), Gigabytes(billion), Terabytes(trillion), Petabytes(quadrillion), Exabytes(quintillion).

Enterprise Storage Options

• Attached storage is attached to a single computer.
• Network-attached storage is storage devices attaching to a network instead of one computer.
• Storage area network is similar to network-attached, except it is a dedicated, special-purpose, high-speed network providing direct connections between data-storage devices and computers across the enterprise.
• Enterprise Storage – NAS (Network-Attach Storage) consists of hard disk storage with its own network address.

Data Input

• Input transfers human-readable data, like a sales order, into the computer system.
• 'Human-readable' is the data that people can read and understand.
• Machine-readable data, like a bar code, can be understood and read by computer devices
• Getting data into the computer system is done in two stages:
• Converting human-readable data into a machine-readable form through data entry.
• Transferring the machine-readable data into the system is data input.

Input Devices

• Keyboards and mice are key input devices
• Speech-recognition technology enables a computer with a source of audio input such as a microphone to interpret human speech as a means of providing data or instructions to the computer.
• Digital cameras record and store images and video in digital form.
• Terminals are electronic or electromechanical hardware devices for entering and transcribing data into a computer system.
• Scanning devices capture image and character data; examples include photocopiers and handheld scanners at Point-of-Sale areas.
• Optical data readers consist of optical mark recognition (OMR), that used on a multiple choice exam to detect a mark on a page and optical character recognition (OCR) to 'read' handwritten or typed characters.
• Magnetic ink character recognition (MICR) devices are used to read 'magnetic ink' at the bottom of bank checks.
• A magnetic stripe card that has a credit card, ID card, or debit card allows input by swiping the card through a reader.
• Chip and pin cards use a computer chip that communicates with a card reader
• Contactless cards contain an embedded chip that only needs to be held close to a terminal.
• Point-of-Sale devices are terminals, such as a bar code reader, used to enter data into a computer.
• Automated teller machine (ATM) devices are special-purpose input/output devices that bank customers use to perform withdrawals and transactions with their bank accounts.
• Pen Input Devices input data by touching a screen with a pen input device, on a tablet PC.
• Touch-Sensitive Screens allow for input
• Radio Frequency Identification reader sends a radio signal that is picked up and returned by a tag, with the reader recognises and identifies the tag.
• Radio Frequency Identification uses a microchip with an antenna for broadcasting its unique identifier and location to receivers.
• London's Oyster card uses RFID technology to let public transport passengers pay their fare; a reader in the station takes payment off the built-in chip.

Output Devices

• Display monitors displays output from the computer like a TV screen.
• Plasma screens use thousands of smart cells (pixels), consisting of electronics, neon, and xenon gases, that are turned into plasma.
• Liquid Crystal Displays (LCDs) are flat displays that use liquid crystals to form characters and graphic images on a backlit screen.
• Organic Light-Emitting Diodes are used in small electronic devices; while LCD screens contain a fluorescent backlight, OLEDs directly emit light.
• Printers and plotters provide paper output.
• 3D Printers take a 3-dimensional model or object stored on a computer to create the object.
• Digital audio player store, organize, and play digital music files like an mp3 player, or iPod.
• Computer-based navigation systems are GPS systems becoming popular with drivers.
• Eyebud screens and 3D printers are specialized output devices.
• E-book readers are electronic books.

Computer System Types

• Handheld computer is also known as pocket PCs, or PDAs for extremely mobile and multi-function devices.
• Smart phone is a handheld computer that can make phone calls.
• Portable Computers include laptops and tablet PCs, audio devices, pagers, tablets, and netbooks.
• Thin Client is low cost, with limited capabilities and only performs essential applications, remaining 'thin' in client applications; it relies on a network connection and centralized server capacity (no extra drives, like CD or DVD).
• Thick Client can do processing at the local terminals.
• Smart Client can do complex processing across the network.
• Desktop PC is the traditional view of a computer.
• Workstation is more powerful than a desktop PC, but looks the same.
• Server is for many users to perform tasks, with large memory and storage capacities, and fast communications abilities; there include:
• Web server handles Internet traffic.
• Internet caching server stores web sites.
• Enterprise server stores and provides access to programs that meet an organization's needs.
• File server stores and coordinates program and data files.
• E-mail server sends and receives e-mails.
• Servers offer the scalability to increase the processing capability of a computer system or network to handle more users or transactions.
• Mainframe Computers are large, powerful computer shared by concurrent users connected through a network, typically kept in data centres with controlled temperature, humidity, and dust levels.
• Mainframe jobs are changing and large information-processing and data-storage roles have been expanded for organizations.
• Supercomputers are the most powerful computers with the fastest processing speed and performance, designed for applications needing extensive and rapid computation; they use specialized graphic processing unit chips which are efficient at manipulating computer graphics.
• Supercomputers perform floating point operations

Considerations when Selecting and Upgrading Computer Systems

• Hard drive considerations should be the capacity, speed, and media capabilities needed.
• Main memory considerations should be more RAM to run software faster.
• Printer considerations should be based on major considerations like price, color, and speed.
• Environmental issues must also be considered when selecting and upgrading.
• Green Computing considers the environment when designing, manufacturing and operating computers.

Summary of Hardware

• Hardware is the machinery that assists in the input, processing, storage, and output activities of an information system.
• Hardware components include: central processing unit (CPU), input/output devices, communications devices, primary storage, and secondary storage devices.
• Secondary storage devices: e.g. magnetic tapes and disks, DVDs, and memory cards.
• Enterprise storage options consist of attached storage, network-attached storage (NAS), and storage area network (SAN).
• Examples of input devices are: keyboards, mice, voice-recognition devices, terminals, scanning devices, and touch-sensitive screens.
• Examples of output devices are: display monitors, liquid crystal displays (LCDs), printers, and plotters.
• Computers can be classified as either special-purpose or general purpose.
• Computer system types are: handheld, portable, desktop, workstations, and servers.