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CHAPTER 2: Hardware and Software Presented by: Arlene N. Baratang HARDWARE Computer Hardware • Computer hardware refers to the various electronic components that are required for you to use a computer along with the hardware components inside the computer case. Hardware Components Communication Device • Communication devices translate one form of communication from an internal or external input device into which the computer can understand, then sending to an output device, or to another computer. Input Device • Input devices, or tools, are used for entering information into the computer. Output Device • Output devices are peripheral devices that convert machinereadable information into people-readable form such as a monitor, printer, plotter and voice output device. Secondary Storage • Secondary storage is also called auxiliary storage, and is used to store data and programs when they are not being processed. Processing Devices: • • • • • • Control Unit Arithmetic and Logic Unit (ALU) RAM Registers Main memory Cache memory Processing Characteristics & Functions Machine Cycle Time • Machine cycle time, or access time, is the time the CPU executes an instruction measured in nanoseconds. Machine cycle time is one measure of processing speed. Clock Speed • Clock speed refers to the number of electronic pulses the CPU produces at a predetermined rate, which affects the machine cycle time. Word Length • Word length is simply a fixedsized group of bits that are handled together by the machine. It usually has a word size of 16, 32, or 64 bits. Memory Characteristics and Functions Storage Capacity • Storage capacity is measured in kilobytes, megabytes, or gigabytes. The term “storage capacity” is used to describe disk drives with storage media such as floppy disks, highcapacity Zip disks, CD-ROMs, and tape cartridges. Types of Memory RAM • Random Access Memory (RAM) has two memory devices, static RAM, or SRAM, and dynamic RAM, or DRAM. SRAM retains its contents while power is on but unleashed when off. DRAM has an extremely short data lifetime, like four milliseconds even power is applied constantly. ROM • Read-Only Memory (ROM) has the ability to retain data and programs even during power failure, and it provides permanent storage for instructions such as programs the computer manufacturer. Programmable ROM • Programmable ROM (PROM) is purchased in an unprogrammed state. The data of an unprogrammed PROM is made up entirely of 1's. Erasable-andProgrammable ROM • Erasable-and-Programmable ROM (EPROM) is programmed exactly like PROM. However, EPROMs can be erased and reprogrammed repeatedly. Hybrid Memories • Hybrid memories can be read and written like RAM, but maintain its contents without electrical power, like ROM. Electrically-Erasableand-Programmable ROM • Electrically-Erasable-andProgrammable ROM (EEPROM) are similar to EPROMs, but the erase operation is accomplished electrically, rather than by exposure to ultraviolet light. Flash Memory • Flash memory devices are high density, low cost, nonvolatile, fast (to read, but not to write), and electrically reprogrammable. Non-volatile RAM • Non-volatile RAM (NVRAM) is like an SRAM with a battery backup. NVRAM operates when the power is turned on, just like any other SRAM. Multiprocessing Parallel Processing • Parallel processing is the simultaneous use of more than one CPU to execute a program. Parallel processing is also by connecting the single-CPU computers in a network, however, this type of processing requires very sophisticated software called distributed processing software. Grid Computing • Grid computing is a form of networking. Grid computing harnesses unused processing cycles of all computers in a network for solving problems. Secondary Storage Devices Magnetic Tapes • Magnetic tapes are magnetically coated strip of plastic on which data can be encoded. Tapes are sequentialaccess media, which means that the tape must go through all the preceding points. Magnetic Disk • Magnetic disk is a round plate on which data can be encoded. There are two basic types of disks: magnetic disks and optical disks. Different Forms of Magnetic Disks: • • • • • Floppy disk Hard disk Removable cartridges Optical disk Redundant Array of Independent/Inexpensive Disks (RAID) Different Forms of Magnetic Disks: • Storage Area Network (SAN) • Memory card, or flash memory card • Memory stick • Universal serial bus (USB) flash drives • MultiMediaCard (MMC) • Secure Digital Card (SD card) Different forms of optical disks: • Compact Disc-Read-Only Memory (CD-ROM) • CD-ReWritable (CD-RW) • Digital Versatile Disk (DVD) Input Devices Input Devices: • Personal computer input devices • Mouse – Mechanical mouse – Optical mouse – Serial mouse – USB mouse – Cordless mouse Input Devices: • • • • • • • Voice recognition devices Terminals Touch-sensitive screens Bar-code scanners Optical data readers Point-of-sale (POS) devices Automatic teller machine (ATM) Input Devices: • Magnetic ink character recognition (MICR) • Radio frequency identification (RFID) Output Devices Output Devices: • Visual Display Units (VDU) Features of a Visual Display Unit – Size – Resolution – Refresh Rate – Type – Color – Scan Pattern Output Devices: • Printers Types of Printer: – Impact printer – Non-impact printer • Plotters Types of Plotter: – Pen plotters – Electrostatic plotters Computer Systems Types of Computer Systems: • • • • • • • Palmtops or PDA Laptops or notebooks Thin Client Workstation Server Mainframe computers Supercomputers Grid Computing • Grid computing is a form of networking. Grid computing harnesses unused processing cycles of all computers in a network for solving problems. Grid Computing • Grid computing is a form of networking. Grid computing harnesses unused processing cycles of all computers in a network for solving problems. SOFTWARE System Software • Operating System (OS) Functions of OS: – Common computer hardware functions – Providing a user interface – Providing a hardware independence – Managing system memory System Software • Operating System (OS) Functions of OS: – Providing networking capability – Controlling access to system resources – Managing files System Software • User interface – Command-based user interface – Graphical user interface (GUI) – Application program interface (API) Current OS • Windows XP • Apple Computer Operating System • Linux Operating System • Palm OS Application Software • Proprietary Application Software – Off-the-Shelf Application Software – Customized Package Application Software • Personal Application Software – Word Processing – Spreadsheet Application – Database Application – Graphics Program – Software Suites Application Software • Workgroup Application Software • Enterprise Application Software Programming Languages • Programming languages are sets of symbols and rules used to write program code for system and application software. Evolution of Programming Languages • • • • • First-Generation Languages Second-Generation Languages Third-Generation Languages Fourth-Generation Languages Fifth-Generation Languages Software Issues and Trends • • • • Software Bugs Open sourcing Software Licensing Global Software Support