Q.1 Define MBR. MBR( Memory buffer register) A Memory Buffer Register (MBR) is the register in a computers processor that stores the data being transferred to and from the devices It allowing the processor and memory units to act independently without being affected by minor differences in operation. Q.2 Define MAR. MAR stand for Memory Address Register This register holds the memory addresses of data and instructions. This register is used to access data and instructions from memory during the execution. Suppose CPU wants to store some data in the memory or to read the data from the memory. It places the address in the MAR. Q.3 Define MDR. Memory Data Register (MDR) MDR is the register of a computer's control unit that contains the data in the computer storage (e.g. RAM) It acts like a buffer and holds anything that is copied from the memory ready for the processor to use it. MDR hold the information before it goes to the decoder. Q.4 Explain Shift micro operation with their types. Shift micro operations are the operations in which the contents of the register can be shifted to left or right. Shift micro operations are used for serial transfer of data. They can also be used with arithmetic, logic and other data-processing operations. There are three types of shift operations: o Logical shift o Circular shift o Arithmetic shift Logical shift o Logical shift can be defined as the shift of the bits to the right or left. o Symbol for logical right shift as shr and for logical left shift as shl. o The following example will help you clear out in this. R1 <- shl R2 Prepared By: Dhaval R. Patel Page 1
R2 <- shr R2 Circular shift o Circular shift also named as rotate shift circulates. o We can connecting the output terminal to the input terminal of the register. o They also shifts only one bit at a single time. For example R <- cir R R <- cil R Cir: circular right shift Cil: circular left shift Arithmetic shift o Arithmetic Shift Operation shifts signed (positive or negative) binary numbers either left or right by multiplying or dividing. R <-- ashl R R <-- ashr R Arithmetic shift-left R Arithmetic shift-right R Q.5 Define Instruction Cycle. Instruction Cycle is the cycle which is used to fetch, decode, execute the instruction of the computer which was given by us. Instruction Cycle has mainly 4 phase o Fetch Phase o Decode Phase o Decision Phase o Execution Phase. Q.6 Explain Push and Pop operation. Push Using this operation we can insert the instruction on top of stack You can push one or more registers, by setting the stack pointer. Thus, pushing is a way of saving the contents of the register to memory. Pop Using pop operation we can delete the instruction from top of stack. You can pop one or more registers, by copying the data from the stack to the register. Popping is a way of restoring the contents of the register from memory. Prepared By: Dhaval R. Patel Page 2
Q.7 Define tri-state buffer. A tri-state buffer is similar to a buffer, but it adds an additional "enable" input that controls the primary input is passed to its output or not. If the "enable" inputs signal is true, the tri-state buffer is normal buffer. If the "enable" input signal is false, the tri-state buffer passes a high impedance (or hi-z) signal, which effectively disconnects its output from the circuit. Tri-state buffers are often connected to a bus which allows multiple signals to travel along the same connection. Q.8 Difference between RISC and CISC. Prepared By: Dhaval R. Patel Page 3
Q.9 Explain I/O BUS and Interface Module. It defines the typical link between the processor and several peripherals. The I/O Bus consists of data lines, address lines and control lines. The I/O bus from the processor is attached to all peripherals interface. To communicate with a particular device, the processor places a device address on address lines. The control lines are referred as an I/O command. The commands are as following: o Control command- A control command is activate the peripheral and to inform it what to do. o Status command- A status command is used to test various status conditions in the interface and the peripheral. o Output data command- A data output command transferring data from the bus into one of its registers. o Input data command- The data input command is the opposite of the data output. It received data from the peripheral and places it in its buffer register. Prepared By: Dhaval R. Patel Page 4
Q.10 List and explain different I/O Command. The control lines are referred as an I/O command. The commands are as following: o Control command- A control command is activate the peripheral and to inform it what to do. o Status command- A status command is used to test various status conditions in the interface and the peripheral. o Output data command- A data output command transferring data from the bus into one of its registers. o Input data command- The data input command is the opposite of the data output. It received data from the peripheral and places it in its buffer register. Q.11 Give comparison between isolated I/O and memory mapped I/O. To communicate with I/O, the processor must communicate with the memory unit. Like the I/O bus, the memory bus contains data, address and read/write control lines. There are 3 ways that computer buses can be used to communicate with memory and I/O: i. Use two Separate buses, one for memory and other for I/O. ii. Use one common bus for both memory and I/O but separate for each. control lines iii. Use one common bus for memory and I/O with common control lines. Q.12 Explain Asynchronous Data Transfer and synchronous Data Transfer. OR Different between Asynchronous Data Transfer and synchronous Data Transfer. In synchronous data transfer there are different clock signal are used between sender and receiver. In Asynchronous data transfer there are common clock signal are used between sender and receiver. Prepared By: Dhaval R. Patel Page 5
Q.13 Explain serial asynchronous data transmission technique. OR Different between serial asynchronous data transmission technique and parallel asynchronous data transmission technique The transfer of data between two units is serial or parallel. In parallel data transmission, n bit in the message must be transmitted through n separate conductor path. In serial transmission, each bit in the message is sent in one path by orderr at a time. Parallel transmission is faster but it requires many wires. And It is used for short distances and where speed is important. Serial transmission is slower but is less expensive. In serial transmission there are three bit are used : i. Start bit ii. Character bit iii. Stop bit i. Start Bit- It is first bit and called start bit. It is always set at zero and used to indicate the beginning character. ii. Stop Bit- It is Last bit and called stop bit. It is always set at one and used to indicate end of characters. iii. Character Bit- It is Bits used in between the start bit and the stop bit are known as character bits. The character bits always follow the start bit. Q.14 Explain strobe control method of asynchronous data transfer. The strobe may be activated by either the source or the destination unit. Data Transfer Initiated by Source Unit Prepared By: Dhaval R. Patel Page 6
o In the block diagram the data bus carries the binary information from source and send to destinationn unit. o The strobe is a single line that informs the destination unit when a valid data word is available. Data Transfer Initiated by Destination Unit o In this method, the destination unit activates the strobe pulse, to nforming the source to provide the data. o The data must be valid and remain in the bus long enough for the destination unit to accept it. o When accepted the destination unit then disables the strobe and the source unit removes the data from the bus. Prepared By: Dhaval R. Patel Page 7
Q.15 Explain Handshaking method of asynchronous data transfer. Handshaking means data accept message reach at sender. The basic principle of the two-wire handshaking method of data transfer is as follow: o One control line is in the same direction as the data flows in the bus from the source to destination. It is used by source unit to inform the destination unit for valid data in the bus. o The other control line is in the other direction from the destinationn to the source. It is used by the destination unit to inform the source whether it can accept the data. Source Initiated Transfer using Handshaking Destination Initiated Transfer Using Handshaking Prepared By: Dhaval R. Patel Page 8
Q.16 Explain Modes of Data Transfer. (Signal Mode Used for 3 to4 marks in exam). OR Draw and explain flow chart for memory operations with DMA OR Explain various modes of data transfer between central computer and peripherals. The data transfer can be handled by various modes. i. Programmed I/O ii. Interrupt-Initiated I/O iii. Direct Memory Access (DMA) Programmed I/O Mode Prepared By: Dhaval R. Patel Page 9
o In this mode of data transfer the operations are used input and output instructions in computer program. o Each data transferr is initiated by a instruction in the program. Interrupt-Initiated I/O o When the CPU receives such an signal, it temporarily stops the execution of the program and used branches to a for service program returns back to task. o Prepared By: Dhaval R. Patel Page 10
DMA o In the Direct Memory Access (DMA) the interface between devices and memory without interface CPU. Bus Request (BR) The Bus Request (BR) input is used by the DMA controller to request the CPU Bus Grant (BG) It inform to outputt devices to used DAM controller. Prepared By: Dhaval R. Patel Page 11
Q.17 Explain CPU-IOP communication. Q.18 What is Flip-Flop? List types of Flip-Flops. Flip Flop is binary storage devices which store 0 or 1 Types of flip-flop o RS flip-flop o JK flip-flop o D flip-flop o T flip-flop Q.19 What is BUS? List Buses used in Computer Architecture. Bus is cannel for transferring data, locate address and control signal transfer in computer system There are three types of them o Data Bus It transfer the data Prepared By: Dhaval R. Patel Page 12
It in bi-direction o Address Bus It Locate address It in one-direction o Control Bus It transfer control signal Q.20 Explain Register transfer Language and their Operation. The symbolic notation used to describe the micro operation transfers among register is called register transfer language Q.21 Explain Virtual Memory. This technique allows users to use more memory for a program than the real memory of a computer. Virtual memory is a common part of operating system on desktop computers. The term Virtual Memory appears to be present but actually is not. Virtual Memory is temporary memory which is used along with the ram of the system.. Prepared By: Dhaval R. Patel Page 13
ADVANTAGES It Allows Processes which need more space. It has good speed using catch memory. This concept is very helpful in implementing multiprogramming environment. DISADVANTAGES Other Applications run slower when they are using virtual memory. It takes more time to switch between applications. Reduces system stability. Q.22 Explain Auxiliary Memory. It is Also called as Secondary Memory, used to store large number of data. It does not lose the data when the device is powered down so it is called non-volatile. It is not directly accessible by the CPU, they are accessed via the input/output channels. Example : flash memory, optical discs, and magnetic disks, magnetic tapes. Magnetic tapes: A magnetic tape consists of electric, mechanical and electronic components to provide the parts and control mechanism for a magnetic tape unit. Magnetic Disk: Prepared By: Dhaval R. Patel Page 14
A magnetic disk is a circular plate made of metal or plastic coated with magnetized material. Flash memory: It An electronic non-volatile computer storage device. It can be electrically erased and reprogrammed, and works without any moving parts. Examples : USB flash drives Optical disc: Its a storage medium from which data is read and to which it is written by lasers. There are three basic types of optical disks: CD-ROM (read-only), WORM (write-once read-many) & EO (erasable optical disks). Q.23 Explain Auxiliary Memory types. Magnetic Disk (Physical Structure of Hard Disk): A magnetic disk is a circular plate made of metal or plastic coated with magnetized material. We can write both sides of the disk. There are several disks locate on one spindle. It have read/write heads available on each surface for read and write data. Bits are stored in magnetized surface circles is called tracks. Tracks are commonly divided into sections is called sectors. Disk that are permanently attached and cannot removed by occasional user are called hard disks. Prepared By: Dhaval R. Patel Page 15
Magnetic tapes: A magnetic tape consists of electric, mechanical and electronic components to provide the parts and control mechanism for a magnetic tape unit. The tape has a plastic coated with a magnetic recording medium. Bits are recorded as magnetic spots on tape along several tracks called RECORDS. Each record on tape has an identification bit pattern at the beg. and the end. R/W heads are mounted in each track so that data can be recorded and read as a sequence of characters. It Can be stopped, started to move forward, or in reverse, or can be rewound,. But it cannot be stopped fast enough between individual characters. Flash memory: It An electronic non-volatile computer storage device. It can be electrically erased and reprogrammed, and works without any moving parts. Examples : USB flash drives Optical disc: Its a storage medium from which data is read and to which it is written by lasers. There are three basic types of optical disks: CD-ROM (read-only), WORM (write-once read-many) & EO (erasable optical disks). Prepared By: Dhaval R. Patel Page 16
Q.24 Explain Associative Memory types. A memory unit which accesses the address of memory is called associative memory. This type of memory is accessed parallel on the basis of data. Operation of them Write operation: When a word is written in an associative memory, no address is given. The memory is capable of finding an unused location. Read operation: When a word is to be read from an associative memory, the contents of the word is specified. The memory find the data which address is match.] Argument register(a): o It contains the word to be searched. o It has n bits(one for each bit of the word). Key Register(K): o It provides key in the argument word. o It also has n bits. Associative memory array: o It contains the words which are to be compared with the argument word. Match Register(M): o It has m bits, one bit corresponding to each word in the memory array. o After the matching process, the bits corresponding to matching words in match register are set to 1. Prepared By: Dhaval R. Patel Page 17
Q.25 Explain catch memory. It very fast and small memory. The average memory access time can be reduced using this memory. So it reducing the total execution time of the program. Operation When CPU needs to access memory, the cache is provide space. If the word is found in the cache, it is read from the cache memory. If the word addressed by the CPU is not found in the cache, the main memory is accessed to read the word. A block of words transferred from main memory to cache memory. If the cache is full, then a block of word is replaced using the replacement algorithm. When the CPU can finds the word in cache, it is said to hit. When the CPU can not finds the word in cache, it is said to miss. The performance of cache memory is frequently measured in terms of a quantity called hit ratio Hit ratio = hit / (hit+miss) The transformation of data from main memory to cache memory is referred to as a mapping process There are three types of mapping: Associative mapping Direct mapping Set-associative mapping Prepared By: Dhaval R. Patel Page 18
Q.26 Explain cache memory mapping process. The transformation of data from main memory to cache memory is referred to as a mapping process. There are three types of mapping: Associative mapping Direct mapping Set-associative mapping Associative Mapping It used The fastest and most flexible cache organization. The associative memory stores both the address and data of the memory word. This permits any location in cache to store a word from main memory. The address value of 15 bits is shown as a five-digit octal number Data value of12-bit word is shown as a four-digit octal number Direct Mapping Associative memory is just like RAM. In general case, there are 2^k words in cache memory and 2^n words in main memory (in our case, k=9, n=15). The n bit memory address is divided into two fields: k-bits for the index and n-k bits for the tag field. Prepared By: Dhaval R. Patel Page 19
Set Associative Mapping The disadvantage of direct mapping is that two words with the same index. In this mapping each word of cache can store two or more word of memory under the same index address. Q.27 Explain Main memory. The all process of computer is execution in the main memory. The main memory is made of RAM integrated circuits chips, but a portion of the memory may be made with ROM chips. RAM Random Access memory Integrated RAM are available in two possible operating modes, Static and Dynamic. ROM Read Only memory Prepared By: Dhaval R. Patel Page 20
Q.28 Explain Main Hierarchy. The memory hierarchy system consists of all auxiliary memory,main memory and cache memory. The auxiliary memory used to store large number of data externally. Example : flash memory, optical discs, and magnetic disks, magnetic tapes. The all process of computer is execution in the main memory. Cache memory is very fast and small memory which catch process from CPU. Prepared By: Dhaval R. Patel Page 21
Q2.9 What is Memory? Explain with their types. The storage data or information in storage devices is called memory - There are two types of memory 1. Primary memory - Primary Memory is internal memory of the computer. - RAM AND ROM both form part of primary memory. - The primary memory provides main working space to the computer. 2. Secondary memory - Secondary memory is external and permanent. - The secondary memory is concerned with magnetic memory. - The user work or large data are storage in secondary memory. - Secondary memory can be stored data on storage media like floppy disks, magnetic disks, magnetic tapes, - This memory can also be stored optically on Optical disks CD,DVD. Q.30 Write the different between ROM and RAM. - Random Access Memory (RAM): o It called random access memory (RAM) because it select the randomly data from storage location. o It have both operation Read and Write. o The storage of data and instructions inside the primary storage is temporary. o Data erase from RAM when power switched off. o It is also known as volatile memories because when power supply is OFF it lost the data. Prepared By: Dhaval R. Patel Page 22
- Read Only Memory (ROM): o The storage of program and data in the ROM is permanent. o The ROM stores some standard processing programs when manufacturers the computer. o The ROM have only Read operation. o The basic input/output program is stored in the ROM. o It examines and initializes various equipment attached to the PC when the power switch is ON. T o It is also known as non-volatile memories because when power supply is OFF it not lost the data. Q.31 Explain RAM with their types. o It called random access memory (RAM) because it select the randomly data from storage location. o It have both operation Read and Write. o The storage of data and instructions inside the primary storage is temporary. o Data erase from RAM when power switched off. o It is also known as volatile memories because when power supply is OFF it lost the data. Static RAM (SRAM) Each cell stores bit with a six-transistor circuit. Store when power ON. Faster and more expensive than DRAM. Dynamic RAM (DRAM) Each cell stores bit with a capacitor and transistor. Value must be refreshed every 10-100 ms. Slower and cheaper than SRAM. Has reduced power consumption, and a large storage capacity. Q.32 Explain ROM with their types. Prepared By: Dhaval R. Patel Page 23
o The storage of program and data in the ROM is permanent. o The ROM stores some standard processing programs when manufacturers the computer. o The ROM have only Read operation. o The basic input/output program is stored in the ROM. o It examines and initializes various equipment attached to the PC when the power switch is ON. o It is also known as non-volatile memories because when power supply is OFF it not lost the data. o There are three types of them. PROM EPROM EEPROM PROM Programmable Read Only Memory (PROM). It is not possible to modify or erase programs stored in ROM, but you can modified program in PROM chip. Programs can not change if power is switched off. So programs or instructions written in PROM or ROM cannot be erased or changed. EPROM: o Erasable Programmable Read Only Memory o EPROM chip can be programmed again after erasing using ultraviolet light. o Erases chip is reprogrammed using a special programming facility. o When the EPROM is in use information can only be read. EEPROM o Electrically Erasable Programmable Read Only Memory o It is similar to EPROM but advantage is that device can be erased without removing it from it s socket. Q.33 Explain Arithmetic Micro-operations with circuit. The basic arithmetic micro-operations are o Addition o Subtraction o Increment o Decrement The additional arithmetic micro-operations are o Add with carry o Subtract with borrow o Transfer/Load Prepared By: Dhaval R. Patel Page 24
Q.34 Explain Logic Micro-Operation and Hardware implementation of logic Micro- bits of operation Logic micro-operations are bit-wise operations, i.e., they work on the individual data There are, in principle, 16 different logic functions that can be defined over two binary input variables However, most systems only implement four of these Prepared By: Dhaval R. Patel Page 25
AND ( ), OR ( ), XOR ( ), Complement/NOT Q.35 Explain Register with their types. Registers are a group of flip-flop which is used for memory addressing, data operation and processing. Some of the registers are general purpose and some are reserved for certain functions. Accumulator register: o It is special data register stores the result of the ALU. Program counter (PC): o Contains the addresses and status of an instructions. o This CPU register always contains the memory address where the next instruction to be performed. Instruction Register (IR) o A special register that holds sequence of instructions to be performed. MBR( Memory buffer register) o A Memory Buffer Register (MBR) is the register in a computers processor that stores the data being transferred to and from the devices Memory Data Register (MDR) o MDR is the register of a computer's control unit that contains the data in the computer storage (e.g. RAM) Prepared By: Dhaval R. Patel Page 26
Q.36 Explain Stack Organization. It's a special region of your computer's memory that stores temporary variables created by each function. It sequence is LIFO There are two operation is there. o Push Using this operation we can insert the instruction on top of stack You can push one or more registers, by setting the stack pointer. Thus, pushing is a way of saving the contents of the register to memory. o Pop Using pop operation we can delete the instruction from top of stack. You can pop one or more registers, by copying the data from the stack to the register. Popping is a way of restoring the contents of the register from memory. Q.37 Explain Polish Notation. OR Example of them A + B Infix notation + A B Prefix or Polish notation A B + Postfix or reverse Polish notation Any arithmetic expression can be expressed in parenthesis-free Polish notation, including reverse Polish notation Prepared By: Dhaval R. Patel Page 27
Q.38 Explain Addressing Modes. Operand can be place either in one of the processor register or in memory. There are different ways to get the operands. The way in which the operand is taken from register or memory is named as addressing mode. Types 1.Immediate Addressing Mode 2.Register Addressing Mode 3.Register Indirect Addressing Mode 4.Direct Addressing Mode 5.Indirect Addressing Mode 6.Implied Addressing Mode 7.Relative Addressing Mode 8.Indexed Addressing Mode 9.Base Register Addressing Mode 1. Immediate Addressing Mode One operand is data and another is register. Move Immediate MVI A, 15h A 15h Here 15h is the immediate operand 2. Register Addressing Mode The operand is specified with register. Prepared By: Dhaval R. Patel Page 28
Instruction specifies the register in which the operand is stored. MOV C, A C A Here A is the operand specified in register 3. Register Indirect Addressing Mode The instruction specifies the register in which the memory address of operand is placed. MOV A, M A [[H][L]] 4. Direct Addressing Mode The instruction specifies the direct address of the operand. The memory address is specified where the actual operand is. Load Accumulator LDA 2805h A [2805] It loads the data from memory location 2805 to A. 5. Indirect Addressing Mode The instruction specifies the indirect address where the effective address of the operand is placed. The memory address is specified where the actual address of operand is placed. MOV A, 2802h A [[2802]] 6. Implied Addressing Mode It is also called inherent addressing mode. The operand is implied by the instruction. The operand is hidden/fixed inside the instruction. Complement Accumulator CMA Prepared By: Dhaval R. Patel Page 29
7. Relative Addressing Mode In relative addressing mode, contents of Program Counter PC is added to address part of instruction to obtain effective address. 8. Indexed Addressing Mode In index addressing mode, contents of Index register is added to address part of instruction to obtain effective address. Q. 39 Explain crossbar switch organization for a multiprocessor organization. Q.40 What is control word? Explain with example. Q.41 Explain functions of BUN, BSA and ISZ instructions for basic computer Q.42 Draw one stage of arithmetic circuit. Q.43 Define fetch, decode and execute phase of an instruction cycle. Q.44 Draw the truth table for logic OR and logic EX-OR micro operations. Q.45 Draw the block diagram for serial transfer. Q.46 Explain the concept of pipeline. Q.47 Define Address Space & Memory Space. Q.48 Draw & Explain Control Unit of Basic Computer. Q.49 Convert following Reverse Polish Notations into infix expressions. (i) AA * BB * - (ii) ABC + * D / E + Q.50 Design a 4-bit Binary Adder-Subtracted Circuit. Q.51 List and Explain Data Transfer Instructions. Prepared By: Dhaval R. Patel Page 30