Computer Science 324 Computer Architecture Mount Holyoke College Fall 2009

Agenda

• Welcome!
• Why take this class?
• Syllabus and administrative details
  • lab access signup sheet
• Review of Bits and Numbers
• Lecture assignment

Examples

Class examples will be listed in this section of each lecture's notes, and can be found in /home/jteresco/shared/cs324/examples on the CSLab Linux systems.

• late - late penalty calculator Graph of the output:

  

• show_bytes - examine endianness

Lecture Assignment

Due at the start of class, Tuesday, September 15.

Turn in short answers to these questions. Please turn in a hard copy (typeset or handwritten are OK). We will discuss these problems during class, so no late submissions are accepted.

1. Make sure you can log into your account on the Clapp 202 Linux systems.
2. Today's class mentioned 5 major levels of abstraction. Briefly describe your level of knowledge of each level. For example, if you have done some assembly language programming, indicate the assembly language you used and how much programming you did in that language.
3. Represent each of the following quantities using each of the following 8 bit representations, where possible: unsigned, signed magnitude, 1's complement, 2's complement. Values are given in base 10, and characters are ASCII. Express each as both an 8-bit binary number and a 2-digit hexadecimal number.
   For example, to represent the value -17, the unsigned representation is not possible, the signed magnitude representation is 10010001₂ or 91₁₆, the 1's complement representation is 11101110₂ or EE₁₆ and the 2's complement representation is 11101111₂ or EF₁₆.
   • 0
   • 11
   • -42
   • 42
   • -127
   • 127
   • -128
   • 128
   • 255
   • the character '6' (see man ascii)
4. Compute the following binary 2's complement problems in 4 bits. Which answers to you trust and why?

    0001      0001      1001      1111
   +0101     +0111     +1111     +0101
    ----      ----      ----      ----