UNIT-3 PC HARDWARE OVERVIEW PART A

Transcription

1 UNIT-3 PC HARDWARE OVERVIEW PART A 1. What is the advance in PC design in various aspects? The PC design has undergone advances in various aspects: Microprocessor used. Peripheral devices supported. Hardware component technology. Operating system capabilities..physical modules/engineering layout. 2. How is the PC used in most of the applications? In most of the applications, PC is used in three ways: For running programs written in higher level languages like BASIC, java etc. For running programs which use application packages like ERP, Tally, etc. For simple operations through packages like WORD etc. 3. Explain in short the three tier communication in a PC? The BIOS DOS, user interaction and the hardware is the three tier communication in a PC. The application program calls DOS for performing specific functions,dos in turn calls respective I/O drivers in BIOS and supplies certain parameter like number of bytes, memory address to the BIOS. The BIOS in turn issues the appropriate commands to the hardware and the status is returned back to the application program through BOIS and DOS. Thus the three tier communication is performed in the PC. 4. List the PC Family of IBM. PC PC-XT PC-AT XT-3270 PC-XT/370 Pcjr Portable Pc PC Convertible XT-286 S.KIRUTHIGA AP/CSE,CCET Page 1

2 5. Five the differences between PC,PC-XT, and PC-AT. FEATURES PC PC-XT PC-AT Year of introduction Micro-processor used Remarks No hard disk ; only floppy disk Hard disk is present Supports multiuser, Multitasking and virtual memory 6. Mention the features of PC and PC-AT. Features of PC Features of PC-AT Uniprogramming Multiprogramming 8-bit Data bus 16-bit,32-bit or 64-bit data bus Maximum 1Mb memory space Beyond 1Mb memory space No cache memory Supports cache memory No virtual memory Supports virtual memory Uniprocessing Supports multiprocessing Uniscalar system Superscalar architecture No power management power management No Multimedia Built-in Multimedia No error detection Parity check, Functional redundancy check, Machine check 7. List the features PS/2. Bidirectional Parallel port Analog Display Silent fan Watch-dog timer 3 ½ FDD Disk cache 8. List the shapes of the system box and give the difference between the two? The system box comes in two forms: Flip-open Pull open type In the flip open model, the top cover can be lifted up and opened fully. In the open condition, the top cover is supported by a hinge lever arrangement. This model is liked very much by service engineers, due to quick accessibility of the parts inside. The pull open model has to be handled more carefully. There are two types. In one version, the cover alone comes out in the front. In the second version, the cover contains floppy disk drives and hard disk drives. In this type, many screws have to be removed and some cables have to be disconnected. S.KIRUTHIGA AP/CSE,CCET Page 2

3 9. What are the signals related to the keyboard?.keyboard Data Keyboard Clock Reset Ground +5V 10. What are the signals related to mouse connector? Mouse data GND Mouse clock +5V 11. What are the main units inside the system box? Switch Mode Power Supply(SMPS) Motherboard Daughterboard s Floppy disk drives Hard disk drives Speaker Power-on Indicator Reset Switch Keyboard Lock Connectors and cables. 12. What is the use of SMPS inside the system box? The SMPS converts AC voltage into different DC outputs. The AT-style SMPS provides DC outputs on two six pin connectors and four (or two ) connectors of four pin each. The two 6 pin connectors (J8 and J9) carry DC power connections to the motherboard. These carry +5,- 5,+12,-12 voltages and a POWER GOOD signal. Some SMPS give a single 12 pin connector. The power-on switch which is a part of SMPS is used to rotate a small fan which is incorporated by SMPS, and that fan provides cooling mechanism in PC. 13. List some of the components of motherboard? Microprocessor,Intel Trimmer capacitor PPI,8255 EPROMs DRAMs Resistors Crystal Jumpers Connectors DIP switch S.KIRUTHIGA AP/CSE,CCET Page 3

4 14. List the special components of the motherboard. Crystal Oscillator Delay line Decoder PROM PAL SIP resistor LED 15. How communication takes place with the HDC? To communicate with the HDC each HDD(ST-506) has two connectors: one 20 pin connector and one 34 pin connector. The 20 pin connector is used for data signals whereas the 34 pin connector is used for control signals. Both the drives are connected to the hard disk controller. It has one 34 pin connector and two 20 pin connectors. There is a separate data cable from HDC to each drive. The control cable is a common cable between the hard disk controller and the drives. The two hard disk drives are mounted either side by side or one over the other. 16. What are the two sections in RAM parity logic and explain them in brief? The RAM parity logic has two sections: Parity generator Parity checker The parity generator an odd parity bit while writing data into RAM. This parity bit is written in RAM. The parity checker checks for the odd parity in the data and parity bit read from RAM. If there is no odd parity, a parity error signal is raised. 17. What are the conditions for generating an NMI interrupt? The NMI logic generates a non- maskable interrupt under any of the three following conditions: Motherboard RAM parity error. Daughterboard RAM parity error. Coprocessor error 18. What are the types of I/O interfaces? Keyboard Display Monitor Printer Floppy disk Hard disk S.KIRUTHIGA AP/CSE,CCET Page 4

5 19. Give the hardware and software interface for the following: a)keyboard b)display Monitor c)printer d)floppy Disk e)hard Disk I/O device Hardware interface Software interface Keyboard Serial communication ; Separate data and clock line Parallel port along with a serial to parallel convertor Display monitor Serial interface ; Composite or TTL video interface Shared memory as Displaybuffer; Programmable controller CRT Printer Serial interface Serial interface compatible to RS232C or parallel through UART; Parallel interface of CENTRONICS compatible interface directly under program control Floppy disk Hard disk Serial interface ;MFM Through intelligent encoded data line which carries both datafloppy disk controller and clock NEC 765/INTEL Commands and parameters are issued as a chain of bytes Serial interface ;MFM encoded data format; Data and clock on the same line ; ST 506/ ST 412 compatible interface Through intelligent hard disk controller. Commands and parameters are issued as a chain of bytes. 20. What is the use of serial to parallel converter in the keyboard interface? The Serial In Parallel Out(SIPO) shift register on the motherboard converts serial data into a parallel byte(8 bit scan code). Once a byte is assembled here, an interrupt (IRO1) is raised to the CPU through the interrupt controller,pic. The keyboard interrupt service routine reads this scan code through PPI-port A, at which the scan code from the SIPO is available. It then stores this scan code in RAM. This scan code is ultimately converted into ASCII code by the software. For diagram refer pageno-144(figure 3.33) S.KIRUTHIGA AP/CSE,CCET Page 5

6 21. What are the two types of CRT monitors that IBM PC supports? 1. Monochrome (black and white) CRT monitor 2. Colour CRT monitor 22. List the types of the CRT controllers and explain them in brief? 1.Monochrome Display Adapter (MDA) 2.Colour Graphics Display Adapter(CGA) The MDA supports only text mode display on monochrome monitors. The CGA supports both monochrome displays and color displays. It offers both text mode and graphics mode display. The basic principle of MDA and CGA is identical. Each of them has a video buffer (Screen memory). This is a shared memory between the CPU and CRT controller. The text or graphics pattern to be displayed on the CRT screen is stored in the video buffer memory by the CPU. The CRT controller reads the contents of the video buffer memory, gets the dot patterns from ROM using video buffer contents and sends the video signal to the CRT monitor along with synchronous signals HSYNC and VSYNC. 23. Give the difference between the two types of CRT controllers? The BIOS programs the CRT controller chip MC6845 in MDA and CGA differently, so as to offer different display resolutions. The MDA supports only the TTL (direct video) type of monitor. The CGA supports both TTL and composite video monitor. 24. When is a 'reset' control classified as hardware and software? The reset switch is pressed by the user to reset the system and start from scratch without switching off. This manual reset is known as hardware reset. The software reset is caused by pressing the three keys CRLT, ALT and DEL on the keyboard simultaneously. 25. How does the interrupt logic handle an interrupt? The interrupt logic receives interrupt requests from different interrupt sources. It raises an interrupt to the CPU. When the CPU acknowledges the interrupt, the interrupt logic sends a vector code corresponding to a high priority interrupt. The CPU uses this vector code for branching to ISR. S.KIRUTHIGA AP/CSE,CCET Page 6

7 PART - B 1. Explain in detail about Hardware-BIOS-DOS Interaction, PC Family OG and NG. Hardware-BIOS-DOS Interaction: Diagram Three-tier Communication in a PC PC Family OG: Difference between a PC-AT, PC and PC-XT PC family IBM PC and Clones PC/AT Major new features PC Family NG : Additional Features in Clones 2. Explain about PC Hardware OG and NG. PC Hardware OG: o Diagram Block Diagram of a PC System Functional Block Diagram of a PC 8088 Microprocessor o CPU o Peripherals PC Hardware NG 3. The system box is the main body of a PC. Enumerate the main unit that can be identified within a system box and give a brief note on each. Switch Mode Power Supply Motherboard Diagram - Power Connections to Motherboard-AT style SMPS Motherboard Components I/O Slot Signals(8088 PC) Mode Switch Diagram DIP Switch Setting - OG Front Panel Indicators and Controls OG Diagram Front Panel Connector New generation front panels Speakers OG Diagram Speaker Connector EPROM/ROM Types OG Floppy Disk Drives Diagram Floppy Signal Cable Hard Disk Drives OG S.KIRUTHIGA AP/CSE,CCET Page 7

8 4. Explain in detail about Motherboard Logic. Diagram Motherboard Logic Reset Logic Diagram - Reset Logic Keyboard Interface Diagram - Keyboard Interface Interrupt Logic Diagram - Interrupt Logic RAM Parity Logic Diagram - RAM Parity Logic NMI Logic Diagram - NMI Logic Memory Refresh Logic Diagram DMA Refresh Logic Wait State Logic Diagram Wait State Logic Bus Arbitration Logic Diagram Bus Arbitration Logic RAM Logic Diagram - RAM Logic CPU Logic Diagram - CPU Logic DMA Logic Diagram - DMA Logic New generation Motherboard logic 5. Explain in detail about Memory space and peripheral Interfaces and Controllers. Memory Space: Memory Space OG Memory Map in IBM PC NG Memory Space Memory Map in AT/286 Peripheral Interfaces and Controllers: Types of IO Interfaces NG I/O Interfaces 6. Explain about Keyboard Interface and CRT monitor Interface. Keyboard Interface: Diagram Keyboard Interface NG Keyboard Interface Parallel Interface Serial Interface S.KIRUTHIGA AP/CSE,CCET Page 8

9 CRT Monitor Interface: Monochrome Display Adapter Color CRT Monitor Diagram Display Adapter Video Buffer as Shared Memory 7. Explain in detail about Floppy Disk Controller and Hard Disk Controller. Floppy Disk Controller: Diagram Floppy Disk Controller Address Decoder Control Port Data Separator Write pre-composition circuit Receivers NG Floppy Disk Controller Hard Disk Controller: Sector Buffer ECC Logic Retry Logic Diagnostics Logic Diagram Hard Disk Controller NG Hard Disk Controller S.KIRUTHIGA AP/CSE,CCET Page 9