Fall 2012: FCM 708 Foundation I

1. Prof. Shamik Sengupta Email: ssengupta@jjay.cuny.edu Fall 2012: FCM 708 Foundation I

2. What is the course about? • An accelerated and selective introduction to three cornerstones of computer science • Introduction to Computer Architecture • Computer Networking • Operating systems Goals: • Learning design and implementation of modern computer systems and networks… • Concepts and Practice • Enjoy… FCM 708: Sengupta

3. Timing and Contact Information • Class meeting time: Thursday (6:15pm – 8:15pm) • Office hours and location: • Office # 06.65.18 New Building • Thursday, 5pm – 6 pm or whenever my office door is open or by appointment • Email: ssengupta@jjay.cuny.edu (Subject: FCM 708) • Office Phone: 212-237-8826 • Instructor’s Website: http://jjcweb.jjay.cuny.edu/ssengupta/ • Blackboard Website: http://doitapps.jjay.cuny.edu/blackboard/ FCM 708: Sengupta

4. Course Material Information • No single textbook • Class notes and slides • References to current materials from journals and magazines • Reading materials from Ebooks from Library • Make sure to have active account at library • Optional Reference Texts: • Computer Organization and Design: The Hardware/Software Interface (The Morgan Kaufmann Series in Computer Architecture and Design), by David A. Patterson and John L. Hennessy • Operating System Concepts, by Abraham Silberschatz, Peter B. Galvin, Greg Gagne • Computer Networking: A Top-Down Approach by James F. Kurose and Keith W. Ross • Computer Networks by Andrew S. Tanenbaum • Fundamentals of Digital Logic and Microcomputer Design, 5th Edition by Mohamed Rafiquzzaman (also partially available in google extended preview) • http://www.ece.rutgers.edu/~marsic/books/QoS/ (online available) • http://inl.info.ucl.ac.be/CNP3 (online available) FCM 708: Sengupta

5. Course Syllabus Overview • Introduction to Computer Architecture • Number systems, • Boolean logic gates, Hardware Logic Simulator • Assembly language programming • Introduction to Computer Networks • Internet Protocol Stack • Application layer, Transport layer, Network layer, Link layer • Practical understanding with wireshark • Intro to Operating systems • Process management • Memory management • Distributed systems, protection and security FCM 708: Sengupta

6. Method of Assessment • Late policy • Submission will not be accepted after due date • Permission needed for exceptional circumstances • Attendance needed. FCM 708: Sengupta

7. Project & Presentation Project: (Approx. 15 weeks time) Individual Project or 2-person team project Collaborated project is expected to show synergy The project paper is due at the last day of class along with presentation Dec 6, 2012 Decide your topic as soon as possible and discuss with me. Start as early as possible. FCM 708: Sengupta

8. Grading Scale FCM 708: Sengupta

9. Questions…??

10. Lecture 1Intro to Computer Architecture

11. What is in a Computer System? • Computer system structure can be divided into three components: • Hardware – provides basic computing resources • CPU, memory, I/O devices • Without the hardware, computation would have been impossible • Application programs – define the ways in which the system resources are used to solve the computing problems of the users • Word processors, compilers, web browsers, database systems, video games • Operating system – “the manager” • Controls and coordinates use of hardware among various applications and users FCM 708: Sengupta

12. Computer System Structure FCM 708: Sengupta

13. Computer System Structure • Major components of the computer hardware - the processor, the control unit, one or more memory ICs, one or more I/O ICs, and the clock • A single printed circuit board usually connects the ICs, making it a microprocessor • Microprocessor – brain of the computers (analogous to human brains) • Responsible for processing of the instructions coming from the software • An interesting fact! • At the lowest hardware level, every operation is performed using logic gates and electric signals (presence or absence of electric signal) FCM 708: Sengupta Image courtesy: Google

14. Number Systems

15. Representation of Numbers • Human: decimal number system • Radix-10 or base-10 • Base-10 means that a digit can have one of ten possible values • 0 through 9. • Computer: binary number system • Radix-2 or base-2 • Each digit can have one of two values • 0 or 1 FCM 708: Sengupta

16. Decimal • These number systems are positional • Multi-digit numbers are interpreted as in the following example • 79310 = 7 x 100 + 9 x 10 + 3 = 7 x 102 + 9 x 101 + 3 x 100 • We can get a general form of this • ABCbase • A x (base)2 + B x (base)1 + C x (base) 0 Remember that the position index starts from 0. Indicate positions FCM 708: Sengupta

17. Binary • Numbers are represented using the digits 0 and 1. • Multi-digit numbers are interpreted as in the following example • 101112 = 1 x 24 + 0 x 23 + 1 x 22 + 1 x 21 + 1 x 20 = 1 x 16 + 0 x 8 + 1 x 4 + 1 x 2 + 1 x 1 • Bit: Each digit is called a bit(Binary Digit) in binary • Important! You must write all bits including leading 0s, when we say 8-bit binary. • E.g., 000101112 (8-bit binary) • EX: Interpret the binary number 010101102 in decimal FCM 708: Sengupta

18. Conversion • We have now learnt how to convert from binary to decimal • Using positional representation • But how about decimal to binary • Simply keep dividing it by 2 • Remainders give the digits, starting from the last remainder • Let’s look at some examples… FCM 708: Sengupta

19. Hexadecimal • Computers use binary number system because of the electric voltage (high or low voltage) • Mostly 8-bit (1 byte) • Very difficult to express • Hexadecimal to rescue • Hexadecimal system is interface between human brain and computer brain • 4 bits are read together and represented using a single digit • Such 4-bits are known as nibble • How many different numbers can be represented using 4 bits? • 16 • Represented by the symbols 0-9 and A-F where the letters represent values: A=10, B=11, C=12, D=13, E=14, and F=15 • Thus each byte is two hex digits • EX: Binary: 110010102 • How to represent this in hex? FCM 708: Sengupta

20. Conversion: Hex and decimal • Hex to decimal • Exact similar to binary to decimal • Use base 16 • Try CA16 • Decimal to Hex • Divide by 16 • Try 20210 FCM 708: Sengupta

21. Notes on Bases • Subscript is mandatory at least for a while. • We use all three number bases. • When a number is written, you should include the correct subscript. • Pronunciation • Binary and hexadecimal numbers are spoken by naming the digits followed by “binary” or “hexadecimal.” FCM 708: Sengupta

22. Ranges of Number Systems Ranges of Unsigned Number Systems FCM 708: Sengupta

23. How about negative numbers • Decimal systems have a minus sign to represent negative numbers • No such scope in binary system • How to solve the problem? • Use the leftmost bit to represent sign (positive or negative) • ‘0’ means positive • ‘1’ means negative • Rest of the bits represent the actual number • For a n-bit number, leftmost bit is the sign bit and rest (n-1) the content • Two approaches were introduced • sign magnitude approach • One’s complement approach FCM 708: Sengupta

24. How about negative numbers (contd.) • Both the approaches have a major limitation! • +0 and -0 have two different representations! • To overcome the problem, a new system was proposed • Two’s complement • Similar to one’s complement system • Solves the drawback. FCM 708: Sengupta

25. Representing two’s Complement Number • Negate a number: • Generate a number with the same magnitude but with the opposite sign. • Ex: 41  -41 • Two steps in binary systems • 1. Perform the 1’s complement (flip all the bits) • 2. Add 1. • Ex: Negate 001010012c (4110) • 1. Flip all the bits: 11010110 • 2. Add 1: 11010110 + 1  110101112c (- 4110) FCM 708: Sengupta

26. 2’s Complement Binary Numbers FCM 708: Sengupta

27. Ranges of Signed Number Systems FCM 708: Sengupta

28. Hardware Architecture

29. Intro to Comp Architecture System Bus Registers Program Counter (PC) Instruction Register (IR) Accumulator (ACC) Memory Address Register (MAR) Memory Buffer Register (MBR) Flag registers Memory • A simplified model of the structure • Central Processing Unit (CPU) • Arithmetic & Logic Unit (ALU) • Control Unit (CU) • Register Array • System Bus • Memory ALU Control Unit CPU Bus Control Bus Data Bus Address Bus FCM 708: Sengupta

30. Arithmetic & Logic Unit (ALU) • ALU responsible for executing operations of arithmetic or logical nature • Works with register array, specifically accumulator and flag registers • Accumulator holds the results of operation performed by ALU • Flag registers indicate through several bit flags the nature of the result • Computation tasks performed by ALU • Addition and subtraction • Multiplication and division • Comparisons and logical tests • Bit shifting • An interesting fact! • At the lowest hardware level, every operation is performed using logic gates and electric signals (presence or absence of electric signal) FCM 708: Sengupta

31. Control Unit (CU) • Control Unit (CU) responsible for controlling the processor operations • Heart of the CPU • CU divided into three components • Decoder • Decode the instructions that make up a program • Break every instruction into three components • Opcode • Operand • Addressing mode • Clock • Responsible for keeping synchronization throughout the microprocessor • Send pulse at regular intervals • Governed by processor clock speed • Control Logic Circuits • Depending on the decoded instructions, create simple logic circuits and send around processor • These control signals inform ALU and register array about what actions they need to perform • By using various logic gates, we will study control logic circuits using Multimedia logic simulator (next class) FCM 708: Sengupta

32. Register Array • Register array – memory locations within CPU itself • Different from actual memory • Register access are faster than memory access • Processors normally contain a register array for accessing quick information during the execution of a program System Bus Registers Program Counter (PC) Instruction Register (IR) Accumulator (ACC) Memory Address Register (MAR) Memory Buffer Register (MBR) Flag registers Memory ALU Control Unit CPU Bus FCM 708: Sengupta Control Bus Data Bus Address Bus

33. Register Array (2) • Register types • Program counter (PC) • Used to hold the memory address of the next instruction that would be executed • Instruction register (IR) • Used to hold the current instruction in the processor while it is being decoded and executed • Accumulator (A or ACC) • Used to hold the result of operations performed by ALU • Depending on microprocessor architecture, there might be more than one ALU • The size of the accumulator corresponds to the size of the processor • 16-bit or 32-bit microprocessor • Memory address register (MAR) • Used to hold memory addresses of the instructions held in the IR • Memory Buffer Register (MBR) • When an instruction or data is obtained from the memory, it is first placed in the MBR FCM 708: Sengupta

34. Register Array (3) • Register types • Flag registers (also known as status registers) • Mostly bit registers • Z-flag (zero flag): indicates if the result of an operation is zero • C-flag (carry flag): indicates if there is a carry in an operation • S-flag (sign flag): used to indicate sign of the result • P-flag (parity flag): used for parity checking • V-flag (overflow flag): used for overflow checking • Index register, X and Y, primarily used to hold addresses • General purpose registers FCM 708: Sengupta

35. System Bus • System bus responsible for data communication between the major components of the microprocessor • Three components • Control bus • Address bus • Data bus • Control bus carries the signal relating to the control and co-ordination • Example: read, write, reset control signaling • Address bus carries the signal relating to the addresses in the memory • Unidirectional (from control unit to memory) • Width of the address bus corresponds to the memory capacity • Data bus used for carrying data • Bidirectional • Width of the data bus can be 8-bit, 16-bit, 32-bit etc. FCM 708: Sengupta

36. Memory Model The way in which the microprocessor stores data • Programmers usually visualize memory as a bunch of sequential spaces • Each space has a unique address that is used to refer the location • Bit size of the address • The number of bits used for the address bus limits the number of memory location 0000 B6 . . . A128 B6 C1 A129 12 A12A . . . 32 FFFE 73 FFFF FCM 708: Sengupta

37. CPU operation • What we have covered so far • Structure and architecture of the microprocessor • Now • How the microprocessor is used to execute a program FCM 708: Sengupta

38. Program execution • Program – a series of instructions for performing some particular task along with data • The executable is nothing other than machine code in binaries understandable by microprocessor • When the user chooses to execute the program, the code is first loaded into the memory • The CPU then executes the program from memory, processing each instruction in turn • This process is called instruction execution cycle FCM 708: Sengupta

39. Instruction set • The instruction set is a collection of pre-defined machine codes recognizable by the CPU • Different processors have different instruction sets for different features, different operational capabilities • But the general structure is same • Opcode, addressing mode and Operand • Opcode: a short code to indicate which operation to perform • Opcodes are also given short names (known as mnemonics) for assembly language purpose and human readability • Operand: indicate the data or where the data can be found • Addressing mode: govern the mode of the addressing, help to specify whether the operand is the data itself or the address where the data can be found (will cover more) • Length of machine code can vary, common length vary from 2 bytes to 12 bytes Opcode Addr mode Operand(s) FCM 708: Sengupta

40. Instruction execution cycle • Instruction execution cycle is the cycle by which each instruction in a program is processed • The cycle is divided in three parts • Fetch instruction • Decode instruction and • Execute instruction FCM 708: Sengupta

41. How “Fetch” works Memory C000. Instr1 C001. Instr2 C002. Instr3 C003. … C004. … C005. … System Bus Registers PC: IR: ACC: MAR: MBR: C001 C000 Instr1 C000 Instr1 ALU Control Unit CPU Bus Control Bus Data Bus Address Bus CU checks MAR and requests the corresponding address content in memory (Fetch) Fetched instruction (Insrt1) is stored in MBR And then in IR FCM 708: Sengupta

42. Decode & Execute • Once the instruction has been fetched, the next step is to decode and then execute • Decode • Check the unique opcode • Example, opcode mnemonic: LDAA, STAA etc. (of course these will be in machine code binary for the microprocessor) • Next check the addressing mode bits • The addressing mode along with operand specifies where the data can be found • The most common addressing modes • Immediate addressing • The data is located within the operands itself, no extra lookup is necessary • Fastest but most inflexible • Direct addressing • The operand specifies the address in the memory where the data is located • Indexed addressing • Addressing is used with relative to index registers, most popular use in arrays FCM 708: Sengupta

43. Hands-on Practice • Let us have some hand-on experience of what we have learnt so far • We will use a simple microprocessor simulator • Motorola 68HC11 FCM 708: Sengupta

44. Reading • 1. Representation of numbers (In BB) • 2. Tips for bits, bytes and other conversions (In BB) • 3. Computer design and architecture by Sajjan G. Shiva (John Jay Library electronic resource) • Chapter 4: A simple computer: organization and Programming FCM 708: Sengupta