Category Archives: 1. Computer Systems

1. Computer Systems, Computing Higher, Homework

Interface Homework

This weeks homework is in Glow learn but here is an offline copy

  1. Describe two ways in which buffers improve system performance
  2. Describe a situation in which spooling would be a useful technique
  3. Give reasons why solid state memory devices are so widely used
  4. Why does an interface have to convert incoming serial data to parallel form?
  5. Why is a buffer an essential part of an interface

For practice – do as an exercise but no need to hand in

Describe a suitable selection of hardware including peripherals to suit the tasks below

  • Producing a school website
  • Setting up a LAN at home
  • Creating a multimedia reference DVD
1. Computer Systems, Computing Higher, Standard Grade Computing Studies

Binary Numbers

Computers store all data as binary, numbers are easily stored this way.

Humans work with a base 10 numbering system (we have 10 fingers), however computers can only store data using electricity (on and off) which is base 2.

This article explains binary in a simple way

128  64  32  16  8  4  2  1 are the headings at the top of the binary numbers so 10001000 would be 128+8 which is 136

Practice here before attempting some bingo

For you exams you will be required to show the working for binary conversion, however, you can check this by using a calculator that has a binary function. The calculator below was found in a local pound shop, you can check if your calculator has binary by checking the buttons for BIN, OCT, DEC, HEX.

You can make a little Binary Calculator with the attached file. The photographs show it in action, simply fold the flaps to make the binary number and add the numbers shown. (teachers note that for 2’s complement just change +128 to -128)

1. Computer Systems, 3. Multimedia, Computing Higher

Cameras and printers

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Today we learned about cameras.

We learned that different types of will have different frame rates. Cheap £20 phones will have very poor video quality. HD video on a phone is better, a digital camera is better than that, a professional camera will be better and a proper TV camera will produce the best quality.

Some cameras have a digital delay.

We also learned that AVI stands for Audi Video Interface. AVI is a windows base format which interleaves video sound and video data.

QuickTime – CODEC was developed by apple but can be used by both Mac and PC. It, like AVI, interleaves sound and video data.

We learned that accurate depends on compression technique, frame rate and resolution.

Speed – Hardware must be fast enough to cope with stream of to memory and to the hard disk.

A digital TV tunes can turn a computer into a digital TV. Good for people who want a computer and TV.

Film replaced by an array of photosensitive cells. Images stored electronically using photosensitive diodes called shared coupled devices (CCDs). The intensity of light is recorded in an image.

Analogue values converted to digital using ADC. Compression usually takes place. Bitmap files are turned into JPEG.

Accuracy is measured in pixels and mega pixels. More is better and less is worse. The accuracy depends on the array of photosensitive cells. The more sensors the smaller they are the higher the resolution.

But depth is in proportion to the number of colours that can be represented. Bit depth is very important on cameras.

Ink is very advanced and difficult to make. That is why it is to expensive.

Inside the pint of a cartage there is a chamber. It is heated and the liquid expands into a bubble. This bubble slowly pops and that is how ink is printed.