COT 4600 Operating Systems Fall 2010 Dan C

COT 4600 Operating Systems Fall 2010 Dan C. Marinescu Office: HEC 439 B Office hours: Tu-Th 3: 30 -4: 30 PM

Lecture 5 – Tuesday September 7, 2010 n n n Last time: n Complexity of Computer Systems n Resource Sharing and Complexity n Bandwidth and Latency n Iteration n Names and The Basic Abstractions Today: n HW 1 – due. n Discussion of “Hints for Computer Systems Design” by Butler Lampson. n Memory. n Interpreters. n Communication links. Next time ¨ Communication links Lecture 5 2

Memory n Devices and systems. Attributes: durability, stability, persistence. Critical properties of memory systems. ¨ Read-Write coherence. ¨ Before or after atomicity. Why is it hard to guarantee the critical properties? Access type: sequential, random. Access time for a disk. Types of addressing: location addressing, associative addressing. n RAID n n n 0, 1, 2, 3, 4, 5, and 6. Lecture 5 3

Interpreters n n n Active elements. Hardware interpreters; software interpreters Three abstractions: instruction reference, repertoire, and environment reference. Flow of control; interrupts. Processors. Finite-state machine with a number of distinguished initial states. Layered organization. Example: a calendar program in Java. Lecture 5 4

Communication links n n n Primitives: send, receive. Wires and networks The Internet ¨ Internet Core and Edge ¨ Hourglass communication model ¨ Protocol stack ¨ The hardware n n Router Network adaptor Lecture 5 5