Introduction to Humanities Computing

Spring 1999

Lecture Nine

Operating Systems

CPM (control program for microcomputers) DOS, Windows Windows 95 Windows NT Mac OS UNIX

History

CP/Mhttp://www.geocities.com/SiliconValley/5711/history.html

BIOS component of CP/MBasic Input Output System

Why is this development important?

Purpose

Manage Files and Programs Manage Devices Manage Network Connection Allow programs to talk to each other Provide standard code (windows, text fields)

Operating systems

Manage Files and Programs

In multitasking operating systems where multiple programs can be running at the same time, the operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn.

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Manage Devices

Operating systems handle input and output to and from attached hardware devices, such as hard disks, printers, and dial-up ports.

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Error Catchers

Operating systems send messages to the applications or interactive user (or to a system operator) about the status of operation and any errors that may have occurred.

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Information Interchange

Codes & Operating systemsUNIX and DOS-based operating systems (except for Windows NT) use ASCII for text files.

Windows NT uses a newer code, Unicode.

IBM's System 390 servers use a proprietary 8-bit code called EBCDIC.

Conversion programs allow different operating systems to change a file from one code to another.

Boot, Run, Open

Your computer typically comes with the OS installed.

You install the applications You launch (run) applications You create documents with the applications You manage the documents (files) with the

File Management tools in the OS.

Interface

How the computer is designed to interact with humans.

What does it show? What does it allow users to do? How does it communicate with users? How does it represent the internals of the

computer?

Lippman on Interactivity

Mutual and simultaneous activity on the part of both participants usually working towards some goal but not necessarily

Stewart Brand The Media Lab: Inventing the Future at M.I.Tp.46

Lippman’s 5 corollaries

Interruptablitiy

Graceful degradation

Limited look ahead

No default

Impression of infinite database

Designer Question

Are Lippman’s corollaries

the best way to judge

an operating system

?