Meltdown CPU security vulnerability

 

Meltdown vulnerability explained in 5 simple steps:

1. Try to read a byte from protected memory. It will fail, but the CPU will still get that value, just will not return it to us.
2. Try to use that byte value as an index in our own array of 256 elements. This operation will fail as well, but as the CPU "knows" the inaccessible value, it will actually use it, will read the corresponding array element and put it into the internal cache.
3. Go through all 256 elements of our array in a loop trying to read them, and measure how long each reading operation takes.
4. The element, which was already accessed based on the "mystery" value, is already in the CPU cache, so it will be read dozens times faster, than the others.
5. The index of that "fast" element is the value, which we tried, but were not allowed to read from protected memory. Now we know it!

Ubuntu 12.04 tweaking

I wrote about experiencing a lot of issues with upgrade to Ubuntu 12.04. I survived that, but had to do a bunch of tweaking to make the system usable, and it's still not ideal yet. :(

Below is a brief list of my tweaks and some useful links.

First, a very helpful article about configuring Unity:
http://askubuntu.com/questions/29553/how-can-i-configure-unity

My Launcher changes:
- Run CompizConfig Settings Manager
- Reduce the Launcher icon size
- Backlight Mode -> Backlight Toggles

Customize workspace layout:
- Run CompizConfig Settings Manager
- Open General -> General Options -> Desktop Size
- Modify Horizontal & Vertical Virtual Size
or
- Run gconf-editor
- Open apps/compiz-1/general/screen0/options
- Change hsize/vsize

Disable workspace switcher animation:
- Run CompizConfig Settings Manager.
- Desktop -> Desktop Wall -> Viewport Switching: set Wall Sliding Duration to 0

Add task bar:
Solution 1: Use tint2
- http://linuxandfriends.com/2011/10/29/how-to-add-a-taskbar-in-ubuntu-11-10/
- The problem with tint2 is it does not work properly with workspaces - it shows all running applications on the task bar

Solution 2: Use GNOME panel
- Run gnome-panel - it will display normal GNOME top and bottom panels
- Use Super+Alt+Right-Click on the top panel, select "Delete This Panel"
- The bottom panel seem to work fine as a task bar
- Customization: http://askubuntu.com/questions/69576/how-to-customize-the-gnome-classic-panel
- cp /usr/share/themes/Ambiance/gtk-3.0/apps/gnome-panel.css ~/.config/gtk-3.0/gtk.css

Pidgin icon is hidden:
It is under the Envelope icon
http://askubuntu.com/questions/67312/how-do-i-enable-the-pidgin-system-tray-icon

Configure time:
http://blog.mattrudge.net/2012/02/11/custom-date-time-format-in-the-unity-tray/

Grub: Save the last selected system for the next boot:
- Open /etc/default/grub:
- Change "GRUB_DEFAULT=0" to "GRUB_DEFAULT=saved"
- Add "GRUB_SAVEDEFAULT=true"


More links:
http://www.webupd8.org/2011/10/things-to-tweak-after-installing-ubuntu.html
http://castrojo.tumblr.com/post/4795149014/the-power-users-guide-to-unity
http://www.techsupportalert.com/content/ubuntu-tips-and-tricks.htm
http://news.softpedia.com/news/Top-10-Ubuntu-11-04-Unity-Panel-Applets-208034.shtml

Quick and easy notepad/memopad for Android: New apMemo

New version of apMemo notepad for Android is released!

apMemo 2.0 New Features:

• New! Graphic and text notes together on one page;
• New! Background can be changed without clearing the note;
• New! Textured backgrounds;
• New! Resizable widgets;
• New! Support for Honeycomb and Ice Cream Sandwich (Android versions 3 and 4);
• New! Long-press actions for the toolbar buttons;
• New! Other improvements and stability fixes;

Existing features have been improved as well:

• Easy visual selection of pen size, color, and background;
• Quick and simple reminder time selection;
• Note thumbnails view;
• Share notes via Facebook, Twitter, GMail, Dropbox and other supporting applications;
• Export note to a file.

apMemo is the simplest and fastest way to create quick handwritten or text notes with reminders!

Work as usual...

No, it's not a flea market. :)

Surviving upgrade to Ubuntu 12.04

I installed Ubuntu 11.10 as a second system on my new PC some time ago, but never had time to fix all the issues with it. One of them was a problem with Logitech wireless USB headset, which was just not working for some reason. Updates and some tweaks did not help, so yesterday I decided to upgrade to the latest Ubuntu 12.04.

What a huge mistake!!!

I was using GNOME desktop - never could get used to the new Unity UI - it was just too limited. After the upgrade my GNOME session was completely broken! The display resolution dropped to default. The two monitors configuration was lost switching to the mirrored option. Windows did not have borders and title bars, they could not be moved or resized, which was especially annoying when I tried to change screen resolution and desktop configuration - I just could not get to the option I needed, as it was out of the screen! Any change to the UI settings (like an attempt to add more workspaces) broke something. A couple times I got an empty desktop without any controls - I could not even log off or restart the system properly! The keyboard shortcuts did not work - in such an empty desktop situation I could not start the terminal. It was a disaster! The system became absolutely unusable!

Luckily I could at least start a browser and access Internet. With help from Google I could fix some issues. The key was to start CompizConfig Settings Manager, which I already had installed - most of the problems with UI are due to the disabled settings there. I enabled Window Decorations in the Effects section; Move Window, Resize Window, and Application Switcher in the Window Management. After that I could at least use the UI. Apparently fixing keyboard shortcuts was not that easy though, as in 12.04 they are handled some special way, and in the GNOME desktop they are simply broken. There were other things still not working properly, so I had to bite the bullet and switch to the standard Unity UI.

Unfortunately this did not fix all the issues. Keyboard shortcuts with the Windows (Super) key did not work, changing those in System Settings - Keyboard - Shortcuts did not have any effect. Looks like the Super key is assigned to Unity, and cannot be used for anything else! Pressing Super+1..9 starts the corresponding shortcut from the launcher, and this overrides any other assignments. I was always using Super+1..4 to switch between the workspaces, and just could not live without it, so had to make it work somehow. Apparently the only way to change that is to completely remove the Super key assignment from the Unity. It can be done in the CompizConfig Settings Manager: Desktop - Unity - Key to show the launcher. After that some shortcuts with the Super key start working - now I can switch between the workspaces, but some keys are still lost. Super+E, which I used to open the Home folder, is still not working. Well, have to use Ctrl+Alt+E for now until I find the solution.

Another annoying thing, which I found, was the mouse sticking at the edge of the monitor when it's moving from one display to another. Luckily it's just an option. Open System Settings - Displays, and turn off the Sticky edges. Another option there, which one might want to change too, is the Launcher placement. I didn't want it to show on both monitors, and thanks to Ubuntu developers, this is customizable.

Well, these are just the first steps with the "latest and greatest" Ubuntu. I'm sure I will find more changes in the system, which break my usual workflow, but at least now it is more or less usable. Oh, and my wireless headset is now working! I have not yet tried the other sound devices though. :)

Using IntelliJ IDEA for Android development

Eclipse is a default IDE for Android development. But personally I have always hated it since the first try. Its UI is very obscure and unobvious. There are really annoying things, like Android Logcat log displayed not as a text, but in a grid, which is difficult to view and copy from; the Logcat window itself being always on top when detached; inability to open two files with the same name from different folders. There are at least five different search commands (three of which open the same Search dialog), but there is no simple "Find Word at Caret" function, which I use a lot. Some other functionality I am used to after many years of work with Visual Studio is missing as well, like quick simple bookmarks, which could be added or navigated to with just one key press.

A while ago I was recommended to try IntelliJ IDEA, and liked it much more! Its developers at JetBrains definitely kept good IDEs in mind while creating their IDEA.

Originally Android development in IntelliJ IDEA was supported via a 3rd-party plugin, then it was included into the Ultimate Edition, but in the latest versions it comes with the Community Edition as well.

The only problem when you are using IntelliJ for Android development is the initial setup for the IDE itself, and for each new project. Every time I start using it on a new system, I spend some time trying to figure out, which bits and pieces have to be configured. Finally I've decided to write this post, so that next time when I'll need it, I'll use this information myself. :)

Here's a brief list of configuration options to set. I am not providing step-by-step instructions at the moment - may do this later, now just trying to document what I've just done, while I still remember it.

Prerequisites: Java SDK (you need v1.6 for Android development) and Android SDK are already downloaded and installed on your machine.

All the options are in the Project Structure dialog, which opens through the main File menu.

Platform Settings section - SDKs:
- Add JSDK: select where Java SDK is located on your system;
- Add Android SDK: browse for the android-sdk-xxx folder, choose it, then when prompted select the JDK first, then the Android target platform;

Project Settings - Project:
- Check the Project SDK - it should have the selected Android platform.

Project Settings - Modules:
- Add Android module by clicking the [+] button on the toolbar;
- Press OK to apply the changes (just Apply does not work for some reason).

Project Settings - Facets:
- Make sure there is Android facet for your module.

If you have several modules, set the proper dependencies in the Modules section.

You'll also need to add Run/Debug configuration. It is done using Run - Edit Configurations menu command. Just click the [+] button on the toolbar in that dialog, select Android Application, type the name for it, select the module to run, and set other parameters if needed.

You are all set!

How to clean your keyboard... using a dishwasher!

Last week I was complaining about the MacBook keyboard. I needed a full keyboard to be able to work, so I asked our IT guys, if there were any external keyboards available, and they pointed me at a cabinet, which had a bunch of old keyboards. OMG! Those keyboards were so dirty, I didn't want even touch them! And it's not just the keys, which were never cleaned. Apparently Apple hardware design is not always that well thought out. Who came up with such a shape, where the outer keyboard body is some kind of an open tray, with the keys inside? Dirt, bread crumbs, hairs, and any small pieces fall down into this tray and stay there between and under the keys and internal keyboard part. And because the tray is transparent, all that dirty stuff is very well visible, which doesn't help.

Well, those were the only keyboards available, so I took one, which at least looked a bit newer under that layer of dirt.

I used to wash a keyboard before, but it was quite time consuming, as I disassembled the keyboard, removed the internal electronic components, washed only the plastic shell with keys, and re-assembled everything back. It looked even more difficult with this Apple keyboard, starting with the screws, which required a small hex screwdriver, and the keys, which construction looked different.

I searched on the Internet and found quite many mentions of the keyboards cleaned in a dishwasher. This sounded like a plan! The keyboard was so dirty and looked so old and abused, that I thought, even if it would die in the process, not many people would regret. On Saturday morning I removed all the clean dishes from our dishwasher, prepared the keyboard by wrapping the cable around and connecting it to one of the USB ports (just so the cable doesn't dangle, and covers at least one USB port), put the keyboard into dishwasher with the keys down, and started a quick wash cycle without any detergent, using just hot water, and with air dry only, without sanitizing (I guess the heated air could melt the plastic).

When the wash cycle was completed, I removed the keyboard, which was full of water, but looked clean. I put it near the heater, not too close so just warm dry air comes to it, and let the keyboard dry over the weekend.

Then was the moment of truth. I connected the washed and dried keyboard to a computer, and it worked! Tested all the keys - no problem at all, and it looks like new!

Using Mac

Recently I changed the job, and at my new work place I've got a MacBook Pro.

Working on a Mac might be quite difficult for someone who was using PCs for 20 years. The Mac OS X UI is not bad, some things are familiar to me after being on Linux for the last couple of years. But one thing on a Mac is very annoying - it's the keyboard, especially on a MacBook.

Using this keyboard for me is like tiptoeing on a mine field. One wrong step and you're dead! Well, it's not really that fatal, but only because there is usually an Undo command available.

The worst thing is the absence of the separate Home/End/PgUp/PgDn keys on a laptop keyboard, so you need to use directional arrow keys with Fn, Control, Option or Command modificators. It is just impossible! Especially because the behavior is inconsistent in different applications.

I've already learned to use the Command key instead of Control, but those arrow keys with modificators drive me crazy! I desperately need a full keyboard!

New PC: Video cards swapping - II

Yesterday I decided to swap the video cards back.

Regardless of the good cooler, the 9800GT was becoming too hot. Apparently there is just not enough air and ventilation - thanks again to Dell motherboard design. The video card is positioned at the very bottom, next to the only PCI slot, so there is less than an inch space between the radiator and the bottom of the main case chamber. The optional fans of the Turbo Module barely fit there, almost touching the wires. Under heavy load the card temperature was over 100°C!

So I decided to return the original ATI HD5670 back - it's a bit less powerful, but being newer it uses less power than 9800GT, so runs much cooler. I put the card back thinking I was just returning to the original configuration, but what a mistake! Well, the old PC didn't have any issues - Windows XP just reused the nVidia driver, I just disabled autostart of the Catalyst, which was complaining about the missing ATI card.

Windows 7 in the new PC didn't have problems either - again, just reused the ATI driver, and I re-enabled the Catalyst autostart.

But completely different story with Ubuntu. It just didn't boot to the GUI! The monitors stayed black and were blinking with the power indicators, which meant there was no proper signal from the video card. Booting in recovery mode and attempt to reconfigure graphics didn't help. Neither the playing with xorg.conf. I removed everything related to nVidia - no luck. Removed ATI drivers as well - nothing... Then somewhere in the logs I noticed mentioning of VMWare and some warnings. I remembered that VMWare gets pretty deeply into the system, it even compiled some kernel modules during installation. So I decided to give it a try. Found how to uninstall it (followed instructions on this page: sudo vmware-installer -u vmware-player), and then after more playing with recovery mode that the system finally could boot successfully into X.

It wasn't the end though. There was no network connection! Apparently when VMWare was ununstalled, it took the network with it. More googling helped to find that "eth0" is not in /etc/network/interfaces anymore. Just added it to the first line ("auto lo eth0"), rebooted, and voilà - it worked!

Now I have just reinstalled ATI drivers, and re-configured the multi-display mode, and finally my computer is working again. No more experiments!

New PC: Video cards swapping

ATI HD5670, which came with my new PC, is not very powerful video card. It's better than some totally budget ones, but it's definitely at the low end. So I decided to compare it with the nVidia 9800GT, which I had in my old PC, and probably swap them. Several years ago 8800GT (which 9800GT is based on, it's basically the same) was almost on the top of the line, and according to the tests I found on Internet, it's still a bit faster than the HD5670.

But first I wanted to replace the cooler on that 9800GT, because the original one was too loud and the card was getting pretty hot on load. Checked what NCIX had on sale, and bought this one - Accelero S1 Rev.2 passive VGA cooler:


The drop in the temperature was huge. With the old cooler the GPU/Ambient temperatures were ~70°C/47°C on idle, and ~80°C/56°C on load. With the Accelero S1 they dropped down to 45°C/34°C and 68°C/43°C accordingly. And that's without fans, in complete silence! Heat pipes are very efficient!

So, I tried both cards in two computers, ran 3DMark06 on both, and here's the result:

3DMark Score	NVIDIA GeForce 9800 GT, 512MB	ATI Radeon HD 5670, 1GB
Old computer (Intel Core 2 Duo Processor E7300 2.66 GHz)	11101	9987
New computer (Dell XPS 9100, Intel Core i7-930 Processor 2.8 GHz)	12984	11452

Based on these results, I'm leaving the 9800GT in the new machine, and will see how it will work.

New PC: Why I don't like brand named PCs

I was complaining about limited SATA connections on Dell motherboard.

Turned out I was wrong. Look at this picture - here are the available connectors:

Those black and blue ones at the edge of the board are used for the the HDD and DVD drives, so there was only one available. But when I was checking BIOS setup today, I noticed it lists more SATA slots. I did one more closer inspection, and finally understood what those numbers and text near the SATA ports on the motherboard mean. Those black and blue connectors are actually double ports! Right under the ones, which are visible and have cables connected, there are two more connectors, which are hidden and not noticeable from any possible angle. And even when I found them, it was very difficult to connect the SATA cables there - without seeing and with limited access.

I've never seen the SATA connectors design like this! If I had a manual for the motherboard, I could figure that out earlier, but alas, seems like there is no such manual coming with Dell XPS.

So, finally it looked like I could connect my other HDD. But that was a hasty conclusion. I was still unable to connect the additional drive, because the SATA power cable was not long enough. It was designed to work only for a specific hard drives position in the original XPS case - the distance between the connectors is very short. I could use one cable with three connectors to power two drives, and the second cable, even though it had three more connectors, could only be used either for the DVD drive, or for another hard drive, but not for both of them. Normally the power supplies have at least a couple of molex connectors. Even though they are not used for the HDDs these days, there are adapters for other components, like fans, special motherboards, PCIe cards. But Dell power supply does not have any, so I couldn't even use this way. I need a SATA power splitter.

How many more surprises should I expect from this Dell?!?

Here's a list of annoyances I had to face with this Dell:

• It is too loud
  
  • Cheap and extremely noisy VGA cooler
  • Stock CPU cooler - noisy and not very good
  • No HDD vibration dampers
• Non-standard design of the motherboard, and no documentation for the motherboard
  
  • A bigger and better 3rd party CPU cooler doesn't fit
  • Difficult to find and use extra SATA ports
  • Not enough fan power connectors on the motherboard
  • Only Dell front panel with non-standard USB ports can be connected (and cannot run without it)
• No molex connectors from the power supply
• SATA power cables are designed to be used only for a specific HDD configuration
• Not enough USB ports on the back

The main idea is: all the components of this Dell PC were designed for a specific configuration. The customization/upgrade/replace abilities are extremely limited. This kind of a PC is intended for the users who are not expected to do anything with it. Want to change something? Order another configuration or even another model!

It is not for me for sure. I've never wanted to buy a brand name PC for myself - saw several of such machines, and every one of them used some custom components, which were difficult to customize or upgrade. This is the first time when I had to get a brand name PC, and it will be the last one!

New PC: Making it quiet - III

As I mentioned in the previous post, the Arctic Cooling Freezer 13 Pro cooler didn't fit into Dell XPS case. What to do? I didn't like the option of exchanging it for a smaller one, as smaller fan would be louder, as its smaller fan needs to rotate on the higher RPM, which eliminates the main goal of making my PC quiet. So I decided to replace the case. I didn't like the XPS 9100 case anyway - it was not designed with silence in mind. Nothing was done to make it quieter - no insulation, the hard drives, DVD drive, and fans are screwed directly to the case, without any vibration dampers. The only good thing - it had 120 mm case fan, which wasn't too loud, rotating at not very high RPM.

I did a lot of research on the quiet PC cases, and selected one, which got a good review on Silent PC Review, and was frequently mentioned in the reviews of other cases, as one of the best - Antec P183:


The main silencing features of this case are: three-layer, sound-deadening side panels and front door; HDD mounting with special cages and silicon anti-vibration grommets; a separate chamber for the power supply in the bottom of the case also helps to reduce noise.

This case was in stock at A-Power, so I bought it from there. I spent the whole evening moving all Dell components from the XPS to this new case. It is slightly bigger than XPS 9100, and with the top fan removed, the Arctic Cooling Freezer 13 Pro fits perfectly.

Of course it didn't go as smooth as I planned. When I installed all the parts, connected everything, and powered it up, the computer didn't want to boot. It kept complaining about the front USB not connected. It also wanted a case fan, so I connected one, and the error message disappeared. But that front USB was painful! First I tried to connect the case front panel - the error was still there on the next boot. Then I got a card reader with ports USB from the old computer, connected that panel, switched on - the same error message. Finally I just disassembled the XPS front panel, removed the card reader with USB ports from there, connected the cables to the motherboard, and that helped! The computer had finally booted. Apparently those original USB ports from the XPS are special. It looks like they have some capacitors, which are probably used to detect the connection, so the motherboard only works with the original USB ports panel!

I didn't really need those ports and the card reader, but didn't have a choice - they had to be connected for the computer to boot, so I put the USB panel inside the case (just used some wires to keep it in place), and connected a couple of USB extenders, so I could at least use those ports. I also found a place for the card reader: could put it into 5" mounts in the front of the case. It doesn't look very aesthetically pleasing, as it's supposed to be covered by the cool shiny semi-transparent panel of the XPS case, and that panel is not detachable. But at least it is connected properly, so the computer boots, and the reader is even accessible, so I could use it to read from the SD cards used in our cameras.

Now, the results.

Arctic Cooling Freezer 13 Pro with heat pipes and big 120mm fan works much better than the stock Intel cooler. Here are the temperatures:

	Idle	Load
Stock cooler	38-40°C	70-73°C
Arctic Cooling Freezer 13 Pro	34-35°C	57-60°C

And most importantly - the computer is now noticeably quieter than before! It is a combination of several things:

• The case is specially designed to be quiet
• Video card cooler is replaced with a big copper one with a low RPM fan
• CPU cooler is replaced with AC Freezer 13 Pro
• Case fans are replaced with SilenX low RPM & low noise ones

It is not dead silent yet, as there are still 5 working fans inside, but the noise they produce is very low. During the day with all the normal sounds around I can barely hear it. And even in the night it's not very noticeable.
I'm happy! :)

New PC: Making it quiet - II

My Dell XPS is still loud. Next component to replace is the CPU cooler. It seems to make the most noticeable sound now, especially on load - when building the CPU is used up to 100%, gets hot, and its fan starts buzzing like it's going to take-off.

After reading some reviews and checking what is available at NCIX, where I usually buy my computer parts, I decided to get Arctic Cooling Freezer 13 Pro:


It is supposed to be very quiet and work much better than the original cooler.

So, I got it, opened the case of my Dell, and found the next surprise: the CPU socket on this motherboard is very close to the edge, so close that the huge radiator of the Freezer 13 Pro does not fit into the place without removing the power supply. What a disappointment!

Now I have to decide what to do - take a smaller cooler so it fits there, or bite a bullet, and move the whole computer into another, even bigger case.

New PC: Making it quiet

This Dell XPS is pretty loud. I knew it wouldn't be the best, but I didn't expect it to be that bad. It might be OK in a regular office environment, but in my home office, where there is no much noise around, the computer is the loudest piece of equipment.

The most annoying thing is the video card. By the way, its brand is "Pegatron" - I've never heard of this name before. Apparently that's a part of ASUS company, which split several years ago. This video card has a very cheap small and extremely noisy fan. I was tired of that noise, and after I got a permission from Mozilla IT guy to modify my PC (as long as I don't break it :)), I started from that annoying little VGA cooler.

I had a pretty big and heavy copper VGA cooler, which I bought several years ago for my HTPC. Since then I upgraded the motherboard in the HTPC, to the one with integrated nVidia 8200, so this VGA cooler was not used. Luckily its mounting screws could be adjusted to fit the holes on the this ATI HD5670, and the radiator did not touch any parts, so I installed it. There was one problem though - the original fan on the VGA cooler was connected to the card itself, and that connector was too small for a 3rd-party cooler fan. Dell motherboard doesn't have any more fan connectors, so I had to be inventive - I cut two pieces from a paper clip, ground them down a bit, inserted into a floppy drive power cable, and connected the fan to that improvised power source. It worked! I put everything together, and now my computer is noticeably quieter without that constant buzz from the video card.

New PC: Need more hard drives

I still had a lot of useful files on my old PC, and it wasn't convenient to access them. It's especially confusing when there are copies of the same files and folders on two machines (like "My Documents" folder, where I had a lot of stuff - from everyday notes, to my financial data needed for tax return). As I've switched to a new PC, I decided to move the hard drive with all my stuff into it. I also had an SSD in the old PC, which I wanted to use.

So, I repartitioned an older 500GB disk, which I had available, moved the system and all the required data to it, got SSD and the HDD from the old PC, opened Dell XPS, ready to install those two drives, and suddenly stopped confused, as there were no place to connect these drives - there was only one SATA connector available! Also there were no place where I could put the SSD so I could screw it to the case - the case was designed only for 3.5" drives.

Well, it's not the first time when I had to invent something, so I managed to connect the SSD and fix it in place, but another HDD was out of luck.
Does this Dell motherboard really have only one extra SATA port?!?

New PC

In January I switched from a contract to a full time position at Mozilla, and as an employee I was eligible for a new computer. I definitely needed a powerful machine, as full Firefox build takes about an hour on my 3 year old PC with Intel Core 2 Duo E7300 CPU. I knew I needed something like Intel i7, so I asked about that and Mozilla ordered me one. I would prefer to assemble a computer myself (at least select the components), but as it had to be ordered and paid by the company, I didn't have much choice, had to go with some brand name. Dell was one of the obvious choices, so I just pointed at some Dell XPS with i7 and configuration close to what I wanted, and it was ordered.

Yesterday it was finally delivered! That's Dell XPS 9100, Intel i7-930, 2.8 GHz, 12 GB RAM, 1TB HDD, ATI Radeon HD5670. Here it is:


This thing is big and heavy! The box, which it came in, was huge! The Purolator guy who delivered it was driving a full size truck, which he backed up to our driveway, and took it all. Normally he drives a regular post office delivery vehicle, but not this time. I guess the big truck was chosen just because of my box. :)

So, I got the new PC set up and running, got Ubuntu installed, copied most important stuff from the old PC, set up Mozilla environment, and tried the build. It took about 20 minutes! A huge improvement compared to the old PC! Now I can build even during the work day, not overnight, as I usually did before.

By the way, it took me a while to install Ubuntu. I wanted 32 bit version, as it's known to have less compatibility issues, but its installation was consistently failing somewhere in the middle. I burned three CDs on two different CD-writers, tried USB-drive - no luck. Only the alternative (text-based) setup worked, though it was very slow. But after I finally installed and ran the system I realized, that 32 bit limits the available RAM to 4GB. Somehow I forgot about that, or rather just didn't think that Linux has the same limitations as Windows (why would it be different?). I just didn't use 64 bit system, and didn't have more than 4GB of RAM in my PC before, so my unconscious mind didn't tell anything. Anyway, I installed the amd64 version, got access to total 12GB of RAM, and now I'm all set.