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Computer System Internals – tutorial questions for week 1
Conversion between decimal and binary is absolutely fundamental for many computer
tasks, particularly in computer networking, hardware, operating systems, graphics... well,
lots of places really!
(1) Please convert these decimal numbers into 8-bit binary numbers
9
00001001
45
00101101
171
10101011
238
11101110
(2) Please convert these binary numbers into decimal
00010001
17
00110101
53
10011010
154
10110111
183
Note
It is very important that you can do these transformations quickly, accurately, and without
calculators (you can’t use them in the exam). You can practise this skill on your own, or with
friends.
On your own, you can use http://www.firstyearmatters.info/binary to test yourself
Alternatively, you can work on your own if you have a way of checking that the number you
have calculated is correct. You can use the Windows Calculator (or other equivalent) to do
this. From the “View” menu, choose “Scientific”. At the top left of the calculator you can
choose the base. If you choose a base, type in the number, and then choose a different
base, the Calculator will convert it for you.
With friends, each of you can invent a random number. Convert it yourself. Pass the
converted number to a friend, without telling them what the original number was, and get
them to convert it back in the other direction. They then tell you what they got, and hopefully
it is the number you started with!
Don’t just practise this until you can get it right.
Practise it until you can’t get it wrong!