Digital Electronics and File Management Unit D

Objectives Introduce Digital Data Representation Introduce Integrated Circuits Explore Processor Performance Factors Understand Computer Memory: RAM Explore Computer Memory

Objectives Introduce Computer File Basics Understand File Locations Explore File Management Understand Logical File Storage Use Files Understand Physical File Storage

Digital Data Representation The form in which information is conceived, manipulated and recorded on a digital device. Uses discrete digits/electronic signals Byte = 8 bits = 1 character

Numeric Data Consists of numbers representing quantities used in arithmetic operations. Binary system, “Base 2” 1,0 (bits - binary digits) On/Off, Yes/No

Coding Systems Depends on computer File headers ASCII (7 bits) Extended ASCII (8 bits - current PCs) EBCIDIC (8 bits - older IBM machines ) Unicode (16 bits - good for languages - future)

Quantifying Bytes and Bits Bit = b Nibble = Half of a byte Byte = B Kilobyte (KB) (1024 bytes) Megabyte (MB) (Million bytes) Gigabyte (GB) (Billion bytes) Terabyte (TB) (Trillion bytes)

Also called a chip, microchip and computer chip. Integrated Circuits A super thin slice of semi–conducting material packed with microscopic circuit elements such as wires, transistors, capacitors, logic gates, and resistors. Bits are represented as electrical pulses that travel over these circuits. Info web: integrated circuits Also called a chip, microchip and computer chip.

Integrated Circuits (cont.) Chips are classified by number of components they contain SSI (small-scale integration), less than 100 components per chip ULSI (Ultra large-scale) over 1 million Semi conducting materials used to make chips Silicon and germanium

Integrated Circuit Uses processors Memory Support circuitry Chip Package Info web: processor update

Processor Packages DIPs (dual in-line packages) DIMMs (dual in-line memory modules) PGAs (Pin-grid arrays) SECs (single-edge contact cartridges)

Microprocessor (Processor) Designed to process instructions Largest chip on motherboard Intel: world’s largest chipmaker (Pentiums) AMD: Cheaper chips (Athlons)

Motherboard Main circuit board

Inside the System Unit The system unit of a PC is the case that houses processing hardware and other hardware. All of the hardware contained within the system unit is connected to the system board or motherboard.

CPU The CPU (central processing unit) does the vast majority of processing for a computer. CPUs contains a variety of circuitry and components and are connected to the motherboard. Also called the processor or microprocessor.

CPU, Cont’d. Processing speed (clock speed) is measured in megahertz (MHz) or gigahertz (GHz) and measures the number of clock ticks per second. A computer word is a group of bits or bytes that a CPU can manipulate at one time. Other factors that affect the speed of the computer include the amount of RAM and cache memory, bus width, and bus speed.

Memory: RAM RAM (random access memory) is the computer’s main memory and is used to temporarily storage programs and data with which it is working. RAM is volatile (erased when the power to the PC goes off). RAM comes in a variety of types, speeds, and size. Types of RAM include: DRAM SRAM SDRAM DDR SDRAM RDRAM DDR-II SDRAM

Memory: Other Types Cache memory—fast memory chips located on or close to the CPU chip (L1, L2, and L3). Registers—high speed memory built into the CPU. ROM (read-only memory)—non-volatile chips inside which data or programs are stored. Flash memory—non-volatile memory that can be erased and reused. Used both within the PC and for portable storage media (e.g digital cameras).

Buses Buses are electronic paths that data travels around on a computer system. Internal buses move data around within the CPU. Expansion buses establish links with peripheral devices. ISA, PCI, AGP, USB, FireWire.

Expansion Slots and Cards Expansion for desktop PCs. Expansion cards can be inserted into expansion slots on the motherboard. Some external devices can be plugged into existing USB or FireWire ports without adding another expansion card. PC cards—used with notebook PCs. Expansion for handhelds and mobile devices—can have proprietary, PC card, or SDIO slot.

Ports Connectors to which devices can be attached. Common ports: Serial Parallel SCSI USB FireWire Network Keyboard Mouse Monitor Modem MIDI IrDA Game

How the CPU Works The CPU is a collection of electronic circuits and components. Impulses from an input device passes through RAM and enters the CPU via a system bus. Within the CPU the impulses move through the circuits and components to create new impulses. Eventually, a set of electronic impulses leaves the CPU for an output device.

Typical CPU Components Arithmetic/logic unit (ALU) Control unit Registers Prefetch unit Decode unit Internal cache Bus interface unit

The System Clock and the Machine Cycle The system clock synchronizes the computer’s operations. The machine cycle is the series of operations involved in the execution of a single, machine-level instruction. Fetch Decode Execute Store

Making Computers Faster Now and in the Future Speeding up your system today. Add more memory. Perform system maintenance. Buy a larger or second hard drive. Upgrade your Internet connection. Upgrade your video card. Upgrade your CPU.

Processor Components

Processor Performance Speed: processor clock set clock speed (MHz or GHz ) Word Size: number of bits the processor can manipulate at one time (32-bit or 64-bit) Cache: high speed memory (kilobytes)

Processor Performance Instruction Set Type: CISC (Complete instruction set computer) RISC (Reduced instruction set computer) Processing Technique: Serial Pipelining Parallel Look at benchmark testing to compare Info web: benchmark Lab: benchmarking

Memory Types Random Access Memory (RAM) Virtual Memory Read-Only Memory (ROM) CMOS

RAM Random Access Memory Temporary (volatile) holding area for data, application software and operating system Expensive chip set Circuitry Less storage than disk Capacitors hold bits Capacity measured in MB (64 - 512 MB) Speed in nanoseconds Makes the most noticeable difference

RAM Types SDRAM RDRAM Synchronous Dynamic RAM fast and cheap DIMMS Most popular RDRAM Rambus Dynamic RAM faster and more expensive RIMMs AND SO-RIMMs

Virtual Memory Disk based Stores parts of programs and data until they are needed by the processor Works with RAM, but is slower

ROM Permanent on a chip from manufacturer Read-Only Memory Permanent on a chip from manufacturer Holds computer start up routine, which are hard-wired instructions Only way to change is to replace ROM chip ROM BIOS (basic input/output system)

CMOS Battery powered More permanent than RAM; less permanent than ROM Complementary Metal Oxide Semiconductor Battery powered More permanent than RAM; less permanent than ROM Stores basic computer configuration Must be updated via CMOS setup program when configuration changed

Computer Ads Includes: capacity, speed, and type of RAM Also maximum RAM that can be installed Example: 512 MB 400 MHZ SDRAM CD screen tour: filename extensions capacity speed type

Computer File Characteristics A collection of data on a storage medium Filename conventions Filename extension CD screen tour: filename extensions .txt .jpg .exe .doc

C:\Music\Reggae\Marley One Love.mp3 File Locations Device drive letters A: C: D: Directory Root Directory (C:\) Subdirectory or folder (C:\Documents) File specification or Path File size and date Filename extension Filename Secondary folder Primary folder Drive letter C:\Music\Reggae\Marley One Love.mp3

Deleting Files Move to Recycle Bin in Windows Undelete Empty Bin

File Management Helps you organize your computer files File/Save and File/Open Utilities like Windows Explorer or MAC Finder list, find, move, copy, delete, rename Save vs. Save As CD screen tour: save as dialog box CD screen tour: operating system file managers

Logical File Storage Filing cabinet or tree model Metaphors to help you visualize files on a storage device Windows Explorer Folder hierarchy Lab: working with Windows Explorer

Using Files Start application (open Word) Create file (type text) Save file (File/Save) Close file and application (File/Exit) Open file again for editing (File/Open) Edit file Save file (with changes, or rename) File/Save File/Save As

Organizing Files On your computer: Give files and folders descriptive names Keep file extensions so files open with correct software Group similar files into folders Organize folders from top-down to make retrieval and backup easier

Physical File Storage Storage medium formatted into tracks /sectors electronically File system keeps track of names and file locations. Windows uses FAT32 OR NTFS Backup your index file Clusters: a group of sectors that speeds up storage and retrieval CD screen tour: formatting a disk

Physical File Storage FAT (File Allocation Table) on each disk keeps track of where all files are and which clusters are empty. If damaged, you lose everything. Defragmentation Utility rearranges files to be stored in contiguous clusters.

Tech talk: How a processor executes instructions Instruction Set is built into processor Instructional Cycle is the execution of a single instruction Interpret Instruction Fetch Instruction Execute Instruction Increment Instruction Pointer

Digital Electronics and File Management End