Category Archives: 6. External Sites

1. Computer Systems, Computing Higher

Computer Systems – Peripherals (arrangements)

During booklet four we will be looking at the following.

  • Description of the use and advantages of buffers and spooling
  • Description of a suitable selection of hardware, including peripherals, to support typical tasks including
    • production of a multimedia catalogue
    • setting up a LAN in a school
    • development of a school website
  • Justification of the hardware selected in terms of appropriate characteristics including
    • resolution
    • capacity
    • speed
    • cost
    • compatibility
  • Description of the features, uses and advantages of solid state storage devices including flash cards
  • Description of the development trends in backing storage devices
  • Description of the following functions of an interface:
    • buffering
    • data format conversion (serial to parallel and analogue to digital)
    • voltage conversion
    • protocol conversion
    • handling of status signals
  • Distinction between parallel and serial interfaces
  • Description and explanation of the current trends towards increasing interface speeds and wireless communication between peripherals and CPU
Computing Higher

Peripherals

Well we are back with a bang.

On Tuesday we went over the 2010 paper we used for exam practice, 2011 Mock. Here is the 2011 Mock Marking Instructions. If you want to ask any question just put it in a comment.

We also started the new peripheral topic in Computer Systems and have covered Keyboards, Scanners & Sound Cards. Search the blog to look for previous articles on these devices, there is more than one. There are a number of non traditional keyboards out there. The net even has articles on how to build a 3D scanner, I would have to say though that milk scanner is a little bit messy. With sound cards we discussed the merits of digital Vs audio, we used scratch’s soundgraph project to look at sample rates.

2. Software Development, Computing Higher

Welcome Back

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I hope you had a restful and pleasant holiday. I decided not to post over the holidays to let you look through the articles on the site.

Anyway now is the time of new year resolutions and I saw these sites and though that it would be a great thing for some people who want to take programming forward or just learn a little more.

Codeyear is a weekly programming tutorial. Notice that I used I word programming and not software development. This is for people who want to learn to code and is less concerned with the waterfall method.

Codeyear was set up by Code Academy, this is a great way to learn how to program. It’s all about the code, there are no distracting videos just a box you type your code into. The language is Java script so you can use your new skills right away creating interactive web sites.

1. Computer Systems, Computing Higher

Factors that effect Computer Performance.

Lots of things effect computer performance. We were looking at a few of them in today’s lesson.

Different types of RAM can have a big impact on the performance of a computer system. Why? Data has to be moved in and out of RAM, the quicker this data can be accessed and moved the faster the processor can get to processing it. Cache improves performance, this high speed SRAM is located close (often in) the processor. It allows the contents of RAM to be stored close to the processor, the processor check here for the next instruction, if its not found then it checks RAM. Although this sounds a bit haphazard, cache can improve the performance of the machine quite significantly.

Then we recapped how RAM effects performance.

  • More RAM means less need to use virtual RAM, therefor an increase in speed.
  • Cache allows for faster access then when the processor gets a cache hits the contents are transferred quicker. there are different types of cache.
  • Increases in RAM speed has failed to keep up with the increase in RAM capacity but different RAM has different clock speeds and even different ways of access.

We went on to look at how the speed and type of a peripheral can effect performance and that they require an interface. The interface allows the CPU to talk to the peripheral. (some brief notes below but we will look at this in more detail in a future post)

Functions of an Interface

  • Buffering – holding data temporarily while in transit between the CPU and peripheral.
  • Data Conversion – changing data into a form the CPU can understand and vice-versa – protocol conversion e.g.
    • serial to parallel
    • voltage conversion
  • Handling Status Information – to show whether the device is ready to receive or send data e.g. is the printer ready or out of paper.

A big thank you to Mr. Allen in Airdrie Academy for letting me cut up and publish his revision notes – AA Computer Performance

2. Software Development, Computing Higher

Scary Software Development Story

All the way through the Software development unit I have tried to instill in you, the idea that programming must be carried out in a rigorous manor. This story shows how important it is that all aspects of software development come together.

The failing may have been a simple HCI problem, if the dashboard had reported the error and asked the driver to restart the car when safe, then all may have been right. Or was is a problem with how the car handled the ice in the first place? In truth the answer may never be known and the error may be unrepeatable, good forward thinking design should be minimise these errors.