CSE3303 Week 2 (Oct 1-5)

First week we showed a movie called "Pirates of Silicon Valley". The main character in the movie is Steve Jobs. The second main character is Bill Gates. If you did not see the movie in class, you may download it from EMule. What you should walk away from this movie is the following:

• The first PC in common use was not the Intel based PC with Windows on it as it was called IBM PC a while back. It was Apple Macintosh. It had a true OS with a character based full-screen GUI. Macintosh reigned as the PC of choice from early 1980's until roughly 1993. Shortly after its introduction, Macintosh featured a true GUI and mouse (inspired by the photocopy machine company Xerox).
• Then there came the IBM PC, gaining in popularity gradually starting in 1987 due to its cheap price and open architecture (ie. no licensing fees unlike Apple). IBM created two giants, Microsoft and Intel, without being able to make any significant fortune from PC business. It even sold its PC division to a Chinese company recently.
• This movie should show you that what seems obvious to you now was not obvious back then. People such as Bill Gates thought all a PC needed was a Basic interpreter. They tried sell simply a Basic interpreter to the company which made Altair. Altair was the first popular Intel based PC. Without Moftware Altair was nothing but an empty tin can (ie. bos teneke kutusu :-).
• While Microsoft did not think that individual users did not need a full-fledged OS on their PCs. Apple was introducing a multi-tasking OS, albeit a cooperative one.
• HP could have all the rights to Macintosh because Steve Wozniak (Steve Jobs' partner) had worked there and had signed documents which transferred the rights of all his future inventions to HP. However, HP was not interested. HP thought Macintosh was ordinary people and ordinary people would not ever need computers.
• ALthough Apple was in the business of making computers for ordinary people, they too thought initially there was no market for it. Like every other computer maker, they tried their chance with businesses, especially banks. However, banks were used to using main frame computers and were not interested in personal computers (called microcomputers at the time as opposed to minicomputers and main frames).
• The turning for Microsoft was the IBM deal. THeir parents knew an influential person within IBM and they had previously sold them a Basic interpreter. IBM was getting ready to compete head-on with Apple to grab a share of an emerging market. IBM was actually buy an operating system called CP/M from Gary Killdall at the time. Gary was already a succesfull and rich businesman at the time due to the quick success of his OS and programming languages. However, he was hard to deal with. (Gary was also from Seattle like Bill Gates.) IBM asked Bill Gates if they could develop an OS similar to CP/M. Microsoft did not have the technical knwo-how to do that. However, they had the business shrewdness to inidrectly achieve that. They bought QDOS for $50K from a company in Seattle. QDOS was a Quick and Dirty Operating System, which was in fact a clone of CP/M. As a result of this, Gary sued IBM later on. Bill Gates called his OS "DOS" which was in fact QDOS. So D in DOS did not really mean Disk, it meant Dirty, but he could not tell that to IBM :-)

I do not have too much time right now, so I will give you the rest of the stuff we talked about this week in headline form:

• Early computers were operated by operators in cooled rooms you were not allowed to enter. They were huge. INput method was front panel switches first, then stripes with holes, punch cards, and then magnetic tapes.
• Batch systems.
• Disadvantage of simple batch systems. Some programs never finish today.
• Multi-programmed and time-shared batch systems. Early form of multi-tasking. Utilize CPU when one process goes to a device.
• An OS introduces convenience, efficiency, and resource uitilization. Convenience is important in PCs. Efficiency is imporatnt in servers and main frames. Resource utilization is important in every computer today because there are always multiple programs running.
• By the way, main frames are still used today widely in banks' headquarters and so on for business computing. ANd they still look for Cobol programmers for example.
• An OS is like government and processes are like citizens. If you need a resource, you can only access through certain procedures, otherwise it would be chaos. Think of traffic lights and so on. An OS is an arbiter.
• We talked about multi-tasking. The difference between multi-processing and multi-tasking. We said from a user perspective multi-tasking and multi-processing, it is almost impossible to tell the difference. A 2x fast multi-tasking system is equivalent to a 2-processor multi-processing system.

  We talked about voluntary multi-tasking, which was the form of multi-tasking in early Macintosh or IBM PC computers. Instead of voultary, people also use the following words: cooperative, collaborative, non-preemptive.

• Modern OSes are preemptive. Early PCs did not have that because there was not enough HW support for it in the processors. In preemptive OSes, a process cannot hang the CPU. There are regular timing interrupts, and the OS takes control at regular intervals through interrupts.

  After the movie we also talked about Intel's history. We also talked about the fact that the movie exaggrates some incidents.

  Late this week, I gave a bonus hw: Install Cygwin.