4Hardware Computers based on: Vacuum tube based - c1940s Transistor based - late 50s; low cost and reliable transistors availableIntegrated Circuit (IC) based - mid 60sLarge Scale Integrated (LSI) circuit based - c80s; These have up to 100,000 transistors on a single chipVery Large Scale Integrated (VLSI) circuit based - c90s; These have >100,000 transistors on a single chip.
5Types of ComputersSmall (Microcomputers or Personal computers) $500 - $7,000Desktop Computers and WorkstationsLaptop ComputersNotebook ComputersPalmtop Computers
6Personal Digital Assistant Known as handheld computersPDAs are portable computers taken furtherPocket sized designed for use on the moveUse a pen as input (write directly to screen)Software 'attempts' to translate handwriting by reference to stored prototypes
7Types of Computers (contd.) Medium-sized computers (minicomputers)- $50,000 - $200, times faster than a PC- Scaled down mainframe- Designed to meet the computing needs of a department or small company. Typically concurrent users.- Can support a number of concurrent applications and often uses a time-sharing operation system that aims to keep the users busy.
8Types of Computers (contd.) Large or Mainframe Computers - $100,000 - $2,000, times faster than a PC- A multi-user computer designed to meet the computing needs of a large organization- Generally refers to computers of the 50s and 60s- Large number of dumb terminals were used for input/output and it had a large number of peripherals attached- Can process a number of applications concurrently. This is known as multi-processing which aims to keep the CPU as busy as possible- Usually housed in special rooms.
9Types of Computers (contd.) Superlarge or Supercomputers-$2 million - $20 million ,000 times faster than a PC- A large number of processors interconnected by a network.- Break up gigantic scientific problems into manageable parallel tasks- Used to simulate nuclear explosions, ocean flow, to track the trajectories of astronomic bodies.
10Computer Operations Input – entering data into the computer; Processing – performing operations on the data;Output – presenting results;Storage – saving data, programs, or output for future use;Communications – sending or retrieving data via the Internet, etc.
12Data Data consists of raw unprocessed facts. The applications and users handle them to turn into Information.Information is structured, ordered and analyzed data useful for decision making. Data is stored in files of different types (documents, spreadsheets, databases, pictures,…)
13Data RepresentationDigital data - is a discrete representation, breaking the information up into separate elements (digits, that is 0 and 1)Bit
14How Information Is Stored Bit is the smallest unit of data, which denotes the binary value of 1 or 0, On/Off, Magnetic/NotByte is the ordered collection of bits(eight bits grouped together)- EBCDIC - Extended Binary Coded Decimal Interchange Code (8 bits per byte)- ASCII - American Standard Code for Information Exchange (7 or 8 bits per byte)Parity bit is the extra bit added to each byte to help detect errorsExample: "HI" =(using binary code)
15The Computing Systems Store, Present, and Help Us Modify: TextAudioImages & graphicsVideo
23Computer Time# PER COMPAREDNAME LENGTH SECOND TO 1 SECONDMillisecond second thousand min 40 secMicrosecond millisecond million daysNanosecond microsecond billion yearsPicosecond nanosecond trillion ,700 years*Computer Frequency inversely proportional to computer time
24Processing SpeedCPU clock speed – measurement of the processing speed, which is rated in megahertz (MHz) or gigahertz (GHz)Highter CPU clock speed more instractions can be processed per secondExample: Core i7 3.2 Ghzfaster thanCore i GHz
25Memory Chip-based storage - primary - amount of the computer's main memory (random access memory or RAM)- secondary - amount of long-term storage available to a computer (computer's hard drive or removable storage media)
26Types of MemoryCache memory and register – volatite, means that their content is rased when power to the memory ceases (like RAM)Read-only memory (ROM) and flash memory - nonvolatite
28RAM (Random Access Memory) Temporary storage for data, programs and the operating system while you are using the PCIt is volatile, meaning that the contents of memory are lost forever when the computer is shut off.
29RAM (contd.) Capacity measured in bytes Type of RAM that can be installed depends on- CPU (32-bit CPU – up to 3 GB of RAM,64-bit – more than 3 GB)- Operating system (64-bit version of Windows Vista – up to 8 GB, up to 16 or more than 128 GB, depending on the edition)
30ROM (Read-Only Memory) Consists of non-erasable hardware modules that store program instructionsIt is non-volatile (that is „read only“)
31Ports and ConnectorsConnectors located on the exterior of the system unit that are used to connect external hardware devicrsEach port attached to the appropriate bus on the motherboard
33Storage SystemStorage medium is the hardware where data is actually stored (CD, flash memory card)Storage device is the type of drive by which storage media is read- internal (inside the CPU)- external (plugged into external port)- remote (located on another computer)
34Access MethodsRandom (direct) access, means that data can be retrieved directly from any location on the storage medium, in any orderSequential access, means that the data can be retrieved in the order in which it is physically stored on the medium
35Hard DrivePrimary storage system used to store most programs and data used with a computer
36Types of Hard Drives- Magnetic hard drive – a hard drive, consisting of one or more metal magnetic disks permanently sealed with an access mechanism and read/write heads, inside its drive
37Types of Hard DrivesSolid-state drive (SSD) – a hard drive that uses flash memory instead of metal magnetic hard disks.
38Disc Access TimeThe total time that it takes for a hard drive to read/write dataInclude three steps:- seek time- rotational delay- data movement timeTypically it is around 8.5.milliseconds
39Optical DisksA type of storage medium read from and written to using a laser beam (Example: CD, DVD)Advantages: large capacity- durabilityDisadvantages: - fragile
40Optical DriveA drive used with optical discs (CD disc, DVD disc)
42Optical Disks (contd.)1) CD-ROM MB (0.7 GB), single layer, red laser, cheap, outdated. For delivering music, software, storing data.2) DVD+-R/RW (Digital Vesatile Disk), 4.7 GB (DVD-5) (single-layer), 8.5 GB (DVD-9) (dual-layer), 9.4 GB (double-sided disk), red laser, current, cheap. For software, movies, data.3) Blu-Ray, 25 GB (single layer), 50 GB (double-layer), may support up to 6-8 layers in the future, blue laser, quite expensive. For high-definition movies, HDTV, data.4) HVD (Holographic Vesatile Disk) TB, 2 lasers, very expensive, emerging.
43Other Types of Storage System Flash memory – a chip-based storage medium that store data using electronsFlash memory card – a small , rectangular flash memory medium (such as CompactFlash)
44Other Types of Storage System (contd.) Holographic storage – the type of three dimension (3D) storage system that uses multiple blue laser beams to store data in three dimensionsAdvantages: - speed- capability- convenient for rarely changed data
46Other Types of Storage System (contd.) Magnetic tape – storage media consisting of plastic tape with a magnetizable surface that store data as a series of magnetic spotAdvantages: - low cost per megabyte
47Other Types of Storage System (contd.) RAID (redundant arrays of independent disks)a storage method that uses several hard rives working togetherPurpose: - to increase perfomance- to protect critical data on storage server (to increase fault tolerance)Techniques: - disc stripping- disc mirroring
49Bus Electronic path over which data can travel Bus width is the number of wires in the bus over which data can travel, affects the number of bits being transmitted at one timeThroughput or bandwidth is the amount of data that can be transferred via the bus in a given time period
57Printers Quality mesured by dots per inch (dpi) Speed measured in pages per minute (ppm)Types: - laser printers (use toner powder)- ink-jet printers (use liquid ink)- special purposes printers (photoprinter, 3D printer)