Wednesday, 17 October 2012

Few Words About You and Textbooks

You read a book if you can open it in any page and from a single line you can explain to your friends the whole page, if from a single paragraph you can tutor the whole chapter. In all other cases you reviewed a book.

Saturday, 16 June 2012

Downgarding Ubuntu? Read this first!

Once made the fatal mistake and upgraded to Ubuntu 12 from Ubuntu 10.04, I had lots of problems: from wrong mouse right clicks in Chrome to corrupted audio drivers... Oh and I forgot, Eclipse didn't started.
I decided to to install the old and the good Ubuntu 10.04 x64. So I've just erased the Linux partition from within Windows, the Grab wasn't erased since Ubuntu was installed from Wubi and now I'm going to install Ubuntu. Again. It's a free, moreover open OS so there is nothing to complain about.

Wubi.exe isn't working and we are downloading ubuntu 10.04 from a torrent. See

Oh, I found an old Wubi which is working and I stopped the torrent download, letting the old Wubi to download ubuntu 10.10 (and this time it is downloading fast).

Spending an hour on tweaking my new old and unsupported Ubuntu, I succeeded to run it. The only thing I did differently is installing 32 bit Java since I had an awful experience with the 64 bit version.

This Ubuntu is intended for my parents. When installing Ubuntu for someone else, remember to:
  • Download and install any IMs they need.
  • Install any needed languages for the keyboard (Go to System->Preferences->Keyboard->Layouts and Layouts->Options->Keys to change layout to set the shortcut.).
  • Tell them the login password and possibly make login to be completed automatically. (Go to System-> Administration-> Login Screen. From there it's straightforward. Remember not to make the default user as root!)
  • Install Java (Oracle's Java! Not the default open source.) and update Flash (just go to youtube and if the videos won't play, click "install missing plugin").
  • Run initial update.

Wednesday, 30 May 2012

Joke (Hebrew)

Q: What method does an object oriented jewish husband that wants to divorce use?
A: Get.

Tuesday, 24 April 2012

Third Math Riddle

There are N men in the room. Every man has a hat. Someone comes and takes all the hats and shuffle them in the middle of the room, than gives every man a hat. The experiment is repeated M times.
Question: how many men in average will receive their hats?
Hint: even if you don't know the relevant material, you still will be able to solve this riddle. How? See rule.

Thursday, 19 April 2012

Second CS Riddle

This time it's going to be CS riddle for the very new students or even school classes. It's very short and no much to write about, but once upon a time I didn't know the answer. So here we go: I give you a range of numbers (from 12 to 120) and I think about one of them (my age). You should guess it by asking me questions while I'm answering with YES and NO only. How would you do it (guess the number via comments) asking me the minimal number of questions?
The rule still applies.

Saturday, 7 April 2012

How to Install Windows 7 from a USB drive on Macbook Air - The Really Working Tutorial

1. To make an installable USB drive and make the Macbook support booting from USB drive, read until "C. Installing Windows on MacBook Air from the USB thumb drive.".

2. Download the macbook drivers for windows from your Macbook by finding Boot Camp Assistant at the utilities folder, and choosing "Download the latest Windows support software from Apple", it's 700MB. Copy them into a USB drive (if you don't have enough space on the first USB drive, copy them into a new one).

3. Partition your hard drive by typing:

sudo diskutil resizevolume /dev/disk0s2 31G MS-DOS "MS-DOS" 1G

at the terminal, change 31G to your desired size  of the OS X's partition and allow the rest to be allocated for Windows (1G will be changed automatically to the maximum allowed size). Terminal can be found at the utilities folder.

4. Shut down your OS X and start your Macbook again, hold down the "alt" key, boot into your USB drive and install Windows. The installation takes 7 minutes.

5. Once done install Boot Camp drivers from step 2 on Windows.

That's it! You have a working dual boot system with working drivers. Enjoy.

See also welcome page - what is this blog about.

Wednesday, 4 April 2012

New Rules and What's Coming Soon

New week and new updates came in. I'm not happy about the traffic in my blog, no doubling of the daily traffic no successful internet innovation. And since I'm not happy with the traffic, nor with the comments there is a new rule: no solution to the riddles until I get at least one comment.

But there are also some good news: I upgraded to Mac, Macbook Air actually and I'm going to write a tutorial about how to install Windows 7 on Macbook Air from USB (flash drive) since I haven't found  100% working tutorial.  

Wednesday, 21 March 2012

Undersea Cables

How do undersea repeaters work? What is the distance between the repeaters? How does a ship that put undersea cables look like? How long can a cable be? The answers are here.

Tuesday, 20 March 2012

Let's Begin: First Math Riddle

Good morning to all my happy (and not so) readers, it took me a while to find a reasonable (or not so) riddle for the first course I'll discuss here. So let's begin with the first math riddle: I lend money from my parents, 100NIS from both of them - 50NIS from my father and 50NIS from my mother, in order to buy a t-shirt for 97NIS. I bought the t-shirt, and got change of 3NIS, while 2NIS I gave to my parents - 1NIS to each of them and 1NIS I kept for myself. Here I tried to calculate the sum of money that was involved in order to know that what I will earn later will be enough, so I started to calculate: the money still I own: 2*49NIS +  the money I returned: 2NIS + the money I had kept for my self: 1NIS = 101NIS.
Where is the mistake?
Imagine there was no 100NIS and 3NIS, but 10,000USD and 2000USD and there was no two parents, but twenty people. The mistake would "cost" me much more if someone would tell me to give just let's say 100.5NIS (and here it would be 11k) to close the deal as a kindly favour for me.

Didn't like the riddle? See one of my favorite riddles Third CS Riddle (short).

Friday, 9 March 2012

Today it's Continuous Blue Screens on My Netbook Lenovo S10

    Looks like a dump file after each blue screen offers a program to be killed - the one that causes all the troubles. I found BlueScreenView wich is supposed to search and show those dump files. I have windows 7 and I read that Daemon Tools can cause it here, but I don't have Daemon Tools so I'll see what it is. By the way, the blue screen is always pixelated so I can't see the problem when it happens.

    I clicked on Google Search in BlueScreenView and it searched for "IRQL_NOT_LESS_OR_EQUAL ntkrnlpa.exe". Looked like I'd have to buy a new RAM or to update some drivers. I chose the later. I ran "sfc /scannow" in DOS... it didn't help much, I got too many unfixable files at C:\Windows\Logs\CBS\CBS.log.

    More and more I'm starting to think about formatting the whole partition (I have Linux with GRUB). The problem with netbook is that there is no a software I can install. Lenovo has the flash drive with the windows on it. I don't. So far I'm getting a blue screen aproximately once a day. 

Something Really Cute for the Weekend

You write your name, they write it everywhere. Check it out:

Wednesday, 7 March 2012


Welcome to the Computer Science blog that will take you all the way towards the degree. I'm a graduating student at the Open University of Israel and I will go through every course in this blog in addition to many other interesting stuff related to Hi Tech and computers. The blog aims to introduce you, the only interested and the very begging students of CS from any university in world to the various contents of the courses through riddles, to wake your curiosity and to bring you some additional material that might interest you as a simple PC or MAC user.

Since the courses at the university are divided into two: math and pure computer science, I will state at titles "Math" or "CS" (i.e Third Math Riddle).

And one more last thing, as I mentioned earlier, the blog targets CS B.A students from all over the world, but since I've studied at the Open University of Israel (OPU), by saying "the university" I will mean the OPU but target any university on the planet.

See also Third Math Riddle - one of my favorites riddles.