1. Computer Science/Ch.3 Data Manipulation 3-1 Chapter 3 Data Manipulation

2. Computer Science/Ch.3 Data Manipulation 3-2 Central Processing Unit CPU: –Arithmetic/Logic Unit(ALU) –Control Unit Register: –A special memory cell within CPU. –Used as temporary holding places for data being manipulated. –Special registers: »Accumulator (AX) »Program counter (PC) »Instruction register (IP) ALU Register Protection Test unit Control Unit Execution Unit Prefetch Unit Paging/ Segment Unit Bus Interface Unit Decode Unit Intel 80386

3. Computer Science/Ch.3 Data Manipulation 3-3 CPU/Memory interface Bus –A special circuit designed for connecting CPU and other components. –Example: »ISA : Industrial Standard Architecture »EISA: Extended ISA »Local bus »VESA »VL-Bus »PCI »…. CPU Memory

4. Computer Science/Ch.3 Data Manipulation 3-4 Stored Program Stored program concept: –Control program is stored in memory –Control unit can extract the program from memory, decode the instruction and execute them. –Machine language –Instruction components: »Operation code (OP-code) »Operand Program execution: –Program counter –Instruction register –Machine cycle: »Fetch »Decode »Execute Fetch Decode Execute

5. Computer Science/Ch.3 Data Manipulation 3-5 Example Instruction Set Example: OP-codeInstruction 001Load 010Store 011Add 100Subtract 101Branch 110Branch if not zero 111Halt Ex. 001 0011 0010

6. Computer Science/Ch.3 Data Manipulation 3-6 Other architecture CISC: –Complex Instruction Set computer –Easy to program –Hard to build –more cost RISC: –Reduced Instruction Set Computer –Hard to program –Easy to build –Less cost Microprogram Microinstruction Machine Language Microprogram Control Circuit

7. Computer Science/Ch.3 Data Manipulation 3-7 Other architecture Pipeline: Throughput: –Total amount of work the machine can accomplish in a given amount of time. Multiprocessor: –parallel processing operator 123 Decode Execute Fetch Fetch DecodeExecution

8. Computer Science/Ch.3 Data Manipulation 3-8 Computer and peripheral Computer/peripheral communication: –Ports –Memory mapped I/O »Screen... –Handshake »Acknowledge –Duplex »Two way –Simplex »One way –Half duplex »Two way but only one way at a time –Full duplex »two way at any time –Controllers: »channel »DMA : direct memory access (DMA Controller) Modem: –Modulator-DEModulator –Example: »2400/9600/14400/19200/28800/33600/56K bps (bits per second) –Baud rate »the rate at which communication line transfer states.

9. Computer Science/Ch.3 Data Manipulation 3-9 Operating System Function of OS: –Resource management: Example: »CPU »Memory »Printer »... –Control date and Its access: Example: »File systems –Efficient use of devices: –Control access to machine: –Standardize the human/machine interface: Example: »UNIX »WINDOWS 95/98 »WINDOW NT

10. Computer Science/Ch.3 Data Manipulation 3-10 Evolution of OS 1940~1950: –Not flexible & efficient Example: Program execution »mounting tapes »placing punched cards in card reader »... –Dedicated to a single job (program ) Batch processing –operator do all things –job queue: »A queue that job can wait for being executed –FIFO »First In First Out –Drawback »the program and data can not be altered once they are in the job queue job queue job execution ResultsUser jobs

11. Computer Science/Ch.3 Data Manipulation 3-11 Evolution of OS Interactive processing –Interactive dialogue –Time-sharing »time slice Network –LAN : local area network –WAN : wide area network –BITNET –Internet –Client/Server job execution Results User /

12. Computer Science/Ch.3 Data Manipulation 3-12 OS Architecture OS components: –Command processor »handle the dialogue with the user –Scheduler »arrange for execution of the program »process –File manager »maintains the records pertaining to the information stored in the mass storage »protection file in mass storage against unauthorized access –Memory management »coordinating the use of the machine's main memory –Resource allocator »coordinate the assignment of peripheral devices within the computer system –Dispatcher »coordinate the switching of the machine's attention among the various processes scheduled for execution

13. Computer Science/Ch.3 Data Manipulation 3-13 OS Architecture OS components: dispatcher memory manager file manager resource allo. scheduler command processor

14. Computer Science/Ch.3 Data Manipulation 3-14 Rudiments of time-sharing Interrupt handling: –Interrupt: –process state: –interrupt service routine : How dispatcher works? –To start one process, the dispatcher jump to the location of memory that process stored. –Before doing this, the dispatcher starts a timer circuit that will generate an interrupt signal after a certain time has lapsed. A B A B Interrupt dispatcher Two processes in a time-sharing system

15. Computer Science/Ch.3 Data Manipulation 3-15 Resource allocation Coordinating the use of resources –Shareable: »Disk –Non-shareable »Tape, printer... –Critical region –Deadlock –Spooling