Posted in Computers & Tech / Hardware Workshop
Author: evought Total-Replies: 12



Actually, that really depends. First of all, it is often the case that the biggest drives on the market have slower rotational speeds (RPM) and longer seek times than the next tier down. The drives are optimized for different tasks, the largest drives often for streaming and high throughput, the smaller often for fast access times.

Additionally, you can get amazing performance out of am array of disks if they do not have to share channels often. This means either having a specialized RAID (Redundant Array of Inexpensive Disks) controller, which are awfully cheap these days, or having enough memory that the things you need from your secondary drive are usually in memory already and your hard drive controller has more options for rearranging the I/O to happen in the most efficient way. But, since IDE RAID controllers with 8 or more channels are now fairly common, that is a good way to go. You can stripe (combine more than one disk into what looks like one big disk for your software), or mirror (have one drive be a real-time backup for the other) or various combinations of the two. In both cases, read operations can be split across multiple drives / I/O channels and in striping, the writes can be spread across multiple drives. Most controllers support configurations where you do striping with some redundancy such that losing one hard drive or possibly even more than one will allow you to recover all of the data.

It has been a few years since I have used this kind of technology and their are brands now I don't even recognize, But Promise is still there and is one of the brands I used on a regular basis. They seem to range from $60-$260 (e.g. http://www.superwarehouse.com/Promise_Fast...X4000/p/1519558 ). We used to have driver problems with Promise controllers running under UNIX (Linux, BSD, Solaris) but never real problems under Windows and they claim to support Linux properly now. I first started playing with these devices in 1994-5. I forget the brand, but it was a 4-channel RAID controller with a 286 processor and upgradable RAM. I had a 486 DX2 at the time and I joked that the hard drive controller was faster and had more RAM than a friend of mine's 286 computer. I used it for my thesis work (computer simulation) to squeeze as much performance out of that system as I could and have a bit of insurance if a drive failed. Because of the mirroring, I got lazy with backups (I had an old QIC tape backup system) and got bit badly when a power surge took out the hard drive controller AND the hard drives in one go. Don't think that mirroring does not mean you need to do backups!

You can also do "software RAID" with Windows, Linux, and Macintosh now. This allows you to do striping and mirroring across multiple drives and even between, say, and IDE and a USB drive, but using software RAID when the performance of the drives and buses are not very close (like say RAID over four internal IDE drives or over four Firewire-connected drives) you will get very strange performance. Usually what I see people do is mirror between master and slave drives on one IDE chain and stripe across two IDE chains. The Promise controller I link to has four independent channels for four drives. You used to see (1997-2002 or so) Promise RAID controllers built-in to quite a few commodity PC motherboards. Asus did that for a while too, and I almost always preferred the Asus controllers.

Server systems often use RAID to increase performance. I have worked with professional RAID setups with as many as 16-32 drives in a single array and multiple arrays. When you have, for instance, 32 fast 20 GB drives, the server can handle a lot of requests simultaneously. Hard drive failures were easy to handle with some of these systems: the front of the bad drive lights up; you unlock the case, pull the handle on the affected drive; slide it out and slide a new one in; you can then take the old one back to the lab to see if it can be fixed or needs to go back to the manufacturer; the server automatically starts rebuilding the blank drive from the mirror.

Anyway, you can make use of your extra hard drives if you want to and you may get surprisingly good performance.

Posted in Computers & Tech / Hardware Workshop
Author: kenobi Total-Replies: 20

Hello. I have bought a new DVD-ROM from LG recently. But after some days it stopped reading any DVD I try. And I tried the same DVDs that it read without any problem just few days ago. And another thing, it reads CDs normally, but this is normal I guess because it doesn't use the same technology to read CDs and DVDs. At first I thought that it might be a software problem because I have installed Nero Image Drive and also Alcohol120% in the time that it stopped to work but than I tried to boot not WinXP with SP2 but a Knoppix Linux from CD and it didn't work either, so I guess it is not a software related problem and therefore it can only be bad hardware. This is waht I think, but it is only my humble opinion. So I would like to know if I am right or if it can be something else. Thanks

Posted in General Discussion / Science & Technology
Author: nakulgupta Total-Replies: 19


Ps:- If anybody feels that this is for credits, then by all means delete it!!

Posted in Astahost / Your Voice! Your Review..
Author: pyost Total-Replies: 34

I have noticed that nobody has made their review of this site yet. It is maybe the name of this site that confuses people, makes them think "is this legal?". The answer is yes. This site is one of the few sites that deal with hacking subject without actually encouraging or, in some way, promoting hacking. Actually, it isn't so bad to encourage hacking, it is bad to encourage cracking. This is how wikipedia defines a hacker:



Anyway, back to the site.

It can be accessed from this address: www.hackthissite.org

The main purpose of this site is to introduce hacker wannabes (again, talking about computer experts) to to complexity of Internet and the variety of options available to a ordinary user.

First of all, there are many challenges.
The easiest are the Basic Web challenges. I have finished them all myself, but with a little help from the forums, since I had no knowledge of different types of injections. After finishing these missions, I know more about javascript injections, UNIX commands and <form> tags.
Next, there are so call Realistic Missions. These are harder to finish, because there are some realistic elements. It is a lot harder to hack (this time I mean hack) a real system than a one which is meant to be hacked. Here you can learn about SQL Injections and other ways to fool the server.
Furthermore, there are Encryption, Programming, Permanent Programming and Application Challenges. I have nothing to say about them, because I haven't tried them yet.

When we move further on, we can see that there are a lot of useful articles, that can help you increase you knowledge. They vary from mission tutorials to complicated techniques.

I haven't mentioned it, but in order to play these challenges, you must register first. This is good, because for every solved challenge you get a certain amount of points. This is where the fun starts. They even give you point to hack their site! I think only two people managed to do this, but there is still time for you to join them

Next, there are a few ways of communication with other players. There is a forum, where you can find hints, but not solutions, for all of the challenges, and also talk to other people about other things. Also, you can talk to them by using IRC chat, which might be even more useful if you want to ask for help.

To sum up, the site is great! Challenges get harder all the time, you can learn really much, and that is not all you can do. There are some really nice people out there to talk to. Negative stuff - well, someone can become a really evil hacker by using this site.

My opinion: 9/10

Posted in Computers & Tech / Programming / Game Programming
Author: unimatrix Total-Replies: 53

I am a 3d animator 1st, game programer about 51st, but I downloaded Game Maker and it seems like a great application and pretty cheap too to create simple and complex games for non-coders. Which could be a blessing if you have some technical skills, but are a better storyteller or creative type that doesn't need 5 years of C++ classes not to mention how to write a graphics shader from scratch.

I typically use Python with Blender 3D because I'm familar with Blender 3d and the game engine is intergrated. But the only time I use the game engine is to conduct rigid body simulations (we do car wreck animations for greedy trail lawyers...yeah, yeah, scum of the earth, but they pay upwards of $5000 per job).

The nice thing about Blender is that it is cross-plaform compatible. SO if you code on a windows machine, it will work in OSX, Linux, FreeBSD, Solaris, or anyother platform supported by Blender3d. Which is kinda cool.

The basic functions are somewhat limiting, but if you learn Python (which isn't as bad as say any version of C) you can do some really powerful stuff and customize just about everything.

Again Blender is designed to create 3D FPS and even RTS games and has a hefty learning curve if you want to learn how to model, texture, and animate. These days developement of Blender is more towards competiting with application like 3D Studio Max, Lightwave 3D, and Maya not as a game creation utility like it was originally designed for, but the game engine is still alive.

Posted in Computers & Tech / How-To's and Tutorials / OS / GNU/Linux
Author: evought Total-Replies: 0

Panasonic Toughbook CF-29 and CF-30 Fedora Linux install; Part II

This is a draft. I need to make an editorial pass and fix the links I have stubbed out.

With recent Linux versions, there are no special flags needed for Toughbooks to boot and run the install. Just boot your chosen media (CD/DVD) and install as usual. If you are simply deleting windows, you can keep things fairly simple by letting the installer erase the disk and lay out partitions for you. Otherwise, you need to delete the second partition and put together a basic layout.

Since this is a laptop, thought needs to be given to security. Laptops are meant to be portable. That makes it easy for you but also makes it easy for someone else to pick it up and go. The cost of the lost hardware is one thing (and maybe you have insurance which will cover it), but criminals don't tend to take privacy very seriously either and you probably have data you don't want them to have: banking information, emails about where your child goes after school, passwords and so forth. If you are using a Toughbook in the first place, in a law enforcement, medical, disaster relief, context, etc., you probably have to worry about protecting other people's data as well. So a good bit of this tutorial is going to cover some ways you can set them up to be secure--- or as reasonably secure as can be expected. I am going to assume you have basic knowledge of Linux installations in general (outside of Toughbooks).

Full Disk Encryption

The first step is going to be Full Disk Encryption (FDE). Linux makes it very easy to encrypt the entire contents of the hard drive. This serves two basic purposes: 1) you do not need to selectively figure out what things are "important enough" to be encrypted and then miss something obvious 2) you ensure that an attacker cannot easily misuse incidental data such as system logs, contents of swap space or file names to figure out what you are protecting and how to get at it. Whenever your laptop is off, its contents are effectively useless to criminals of modest resources. The important thing to realize is that whenever your computer is left on, like when you get up from the table to get your coffee order, FDE does you know good whatsoever, even if your screen is locked. A criminal that takes your laptop while on or suspended can bypass the encryption. Sophisticated criminals can recover information from RAM even if it was just very recently on.

Start by creating a /boot partition. It has to be unencrypted and big enough to hold the kernel and libraries needed to bring the system up and decrypt the rest of the hard drive. My /boot partitions end up being about 500 MB just as a nice round number.

Next create an LVM Physical Volume and let it fill the rest of the disk, checking the box to encrypt the volume. Now create a Logical Volume Group in the Physical Volume. Create a swap partition (usually about the same size as your RAM, so for the CF-29, I create a swap about 768 MB). Create a root partition ("/") for your system files. Since I have plenty of HD space, I set these at ~50GB to make sure I have plenty of space to install packages and applications. Create a home directory for your data and documents. Do not check "encrypt" for these partitions since the container, the "Physical Volume" they are in, is already encrypted. Link to Fedora LVM chapter.

I tend to not let the home directory fill the entire disk. 50 GB is more than adequate to start out and the Linux Logical Volume Manager lets you add space to a file system later on. It is a bit more tricky to shrink one on the fly. By leaving unallocated free space, you have something to play with if you run out of room somewhere or want to create a new partition. If you continue the install from here, you will be asked for a password for the encrypted volume. This password will be required every time you boot and every time you recover from hibernation, so it has to be something you can type and remember, but it should also be a good password of probably 8+ characters, mixed punctuation, not a dictionary word, and with digits or symbols thrown in. It is possible to brute force a bad password and then the rest of your protection can be unravelled.



This leaves you with an unencrypted /boot, an encrypted swap, root filesystem and home directories. An attacker who takes your laptop powered off will have access to your Windows partition and /boot. They cannot readily access your LVM physical volume (AES encryption by default and reasonably hard to crack if you have a good password). Your swap space, which might contain encryption keys for the physical volume, is also protected. System logs which might have information about your documents and habits, systems you connect to and so forth, are encrypted along with everything else.

If your data is important enough or if you have pissed off a computer nerd, someone could modify your /boot data, install a keylogger, and record your encryption password (or something equally sneaky). The Toughbooks have quite a few options for locking the laptop at the BIOS level. The easiest way is to simply turn on the BIOS password and require it at boot and at access to the BIOS. You can also set a Supervisor password to lock the BIOS and system setup menus and a separate User password to boot the laptop (say, if you set up the computer but someone else uses it). This keeps someone from easily booting up, tampering with your software and shutting back down.

Your nemesis could remove your hard drive and try to get at your data that way (protected by the encryption) or tamper with /boot, but they are not going to do that while you pick up your coffee at the Starbucks counter. The CF-30's have a TPM processor, a system-security chip which can be used to thwart even that: telling you at bootup that your system software has not been tampered with or encrypting the entire contents of your drive with the internal crypto system. I may cover TPM configuration in a later post, but it should be mentioned that there is a simpler method: put /boot on a USB dongle and carry it with you. This is inconvenient with the CF-29 and its single USB connector, but easy with the CF-30. Insert link to article on removable /boot and TPM. The DOD method I have witnessed is also low-tech and effective: pull the removable hard drive and drop it in a safe when not in use. This is the reason Toughbooks have easily removable hard drives.

The rest of the install

After all of that, the rest of the install proper is pretty simple. I selected the Desktop and Software Development package categories. We will need the software development tools to build tools to set up the touchscreen properly, which I will cover in the post-install. You might as well just check to box now and get it out of the way.

Oh, and by the way, if you choose to set up the network during the install, remember to flip the CF-30's wireless cut-off switch to "On" before you spend thirty minutes trying to figure out why the network isn't working. A green LED will light up to tell you it is activated.

Post install

Fedora Linux will bring you into a setup program on your first successful boot. Here you will set up the network (if you have not already), set a root password, and create a non-root user. The root password will be very rarely used, except critical system maintenance, and if you hose your normal account. Make it a good password and then write it down somewhere safe (like in your key safe or a document safe). Your user account password will be used for every day logins and through the "sudo" tool for routine system maintenance. Make at least one of your user accounts an "administrator" so that this will work properly. If you are truly paranoid, you will have a normal user account you use every day and another with the administrator flag checked. This means that after visiting a malicious web site which takes over your browser, they won't be able to install a boot sector virus. I'll leave that decision up to you and will present another option further on. I often set the administrator flag on a new system and once I have it set up the way I like it, remove it from my normal user and create a separate administrator account for routine maintenance.

Updates

After you finish the setup and get to the login screen for the first time, you will want to run the Software Update program to get all of the security patches and updates. Since FC-15 has been out for a while, expect to spend some time even with a good network connection.

There seems to be a common bug in FC-15 where you get an error message involving "fedora-release-rawhide" in your first update. I solved this by opening a terminal and running "sudo yum update fedora-release-rawhide" and when that finished, "sudo yum update" to do the updates manually (which is always an alternative to the GUI Software Update program). Your mileage may vary.

Gnome

If you have not used Gnome 3 before (the graphical desktop used by FC-15), it may take some getting used to. I have found that I like it OK on the CF-30 and it is reasonably snappy. On the CF-29, in Gnome's "fallback mode" for those of us in technological backwaters, it is actually quite painful since most of the new ways to get to the applications and settings you need are not there and the old ways are not there either. Reading a short Gnome-3 tutorial is worth the time and things will not make much sense if you don't. On the CF-29, I install a package called "Gnome Do". This allows me to hit Command-Spacebar and pop up a search prompt. I can then start typing the file or program I want, hit tab when it comes up with the right answer, and then run or open it. So, I can start typing "Terminal," about when I get to the r, it pops up the correct program, I hit Tab and Enter and have a terminal window--- much faster than trying to get through the menus, especially before I get the mouse working properly. I intend to figure out how to get WindowMaker (another desktop option) working on FC-15 but have not yet done so.

Touchpad/Touchscreen

On the CF-29, you will notice that the touchpad is painfully slow. It may take you about a thousand years to move the mouse cursor from one corner to the other. The touchscreen won't work at this point, either. If you tap on a spot on the screen, the mouse cursor will jump but won't go quite where you want it. On the CF-30, the touchscreen will misfunction the same as the CF-29 but the touchpad will work. If the CF-30 touchpad is slow for you, you can adjust it from System Settings->Mouse and Touchpad. System Settings can be gotten to a few different ways, one of which is by going to your account name in the upper right corner of the screen and clicking to pull down that menu.

The CF-29 touchpad cannot be adjusted so easily. After much frustration and trial and error, I fixed it by adding the following to a file called .xinputrc in my home directory:



Create this file, add that line, and the save it. Make it executable ("chmod u+x ~/.xinputrc"). Now create a directory called /bin, and create a file called "fixtouchpad" with the following:



Make this one executable as well. I tend to add ~/bin to my path in my .bashrc and put various little tools in it. Now, in case this does not work for you, let me explain what it does. "xinput" is a tool for tweaking the behavior of various X Windows input devices: mice, trackpads, trackballs, etc. This line sets the acceleration (ptr-feedback) for a device numbered 10 which happens to be the builtin trackpad for me. It sets the acceleration to 1.5 starting after 10 pixels of movement and counting by 1 px at a time thereafter. Play with these numbers to find what works for you. According to the documentation, "1.5" should not work--- it is supposed to be a whole number--- but it does work and seems to behave better than using "2" for me. You can run xinput in terminal with different settings as many times as you need and then copy the numbers into fixtouchpad. "xinput --get-feedbacks 10" might also be useful to you. When you log out and back in, your .xinputrc should be run automatically and the touchpad should work.

If this does not work at all for you, you may need to figure out the device number. xinput has a manpage ("man xinput"). "xinput --list" will give you information on all the input devices:



You are looking for the "PS/2 Touchpad". .xinputrc will run fixtouchpad for you every time you log in, but your trackpad settings will go away when you hibernate and thaw. That is why I put the settings in a separate script. When I come back from hibernate, I run fixtouchpad and go (Actually, I type "fixt|TAB|", the shell autocompletes the command, I hit Enter and go. I'm lazy. As soon as I find out how to run this automatically every time I come back from hibernate, I will.)

OK, so now the system is relatively usable. Let's fix the touchscreen. As it turns out, the touchscreen works fine, unlike previous version of Linux. The problem is that each touchscreen is just a little different from every other, and it needs to be calibrated using a tool called xinput_calibrator. The normal Gnome tool will not work. Download the "source tarball" of xinput calibrator from Find link. Unpack it, configure, compile, and install. e.g.:



Now you can run "xinput_calibrator --output-type xorg.conf.d". It will ask you to tap in various places (best to do with the stylus so it is precise) and then will spit out the settings you need. Cut and paste them into a file called "/etc/X11/xorg.conf.d/99-calibration" . You will need to edit the file using sudo, as it will be owned by root. Mine looks like this:



Log out and restart. Your touchscreen should now work. It is fine-grained enough in Linux to do some handwriting recognition and sketching using the stylus, though the screen is akward to write on.

Stay tuned for Part III with even more Toughbook-tweaking madness!

Posted in General Discussion / Computer Talk
Author: Quatrux Total-Replies: 28

I always use the Opera password manager, for me personally it is very useful. I am the only one who am using my computer and every time I visit a site I just push ctrl+enter and thats all, I get logged in into any of the sites I saved the password and it is so easy, you log in the for the first time and the browser ask you to remember or not now and you can choose for the entire domain or only for that page.. Moreover, if the site has two account, say usually like google, gmail, adsense, I just need to choose which username to use. For me it is one of the most useful tools in the browser. And I usually logout/signout from any site.

I just don't like, for example, when I reinstall windows and the password manager again is empty, even though it was a long time ago.. I don't like to do all over again to save the session. But one bad thing about password managers is that it really is much easier to forget the username+password you're using. I have about 4-5 main passwords usually with the same username, but sometimes I just forget where which one I use, due to the password manager usage, that is why I am using the great program KeePass, to save all my passwords and of course if I ever have a computer failure, I have them somewhere on my notes

The bad things about having passwords on a note, you leave the paper on your desk or something like that and invite some friend to your house for a beer or something and usually they can see it if they will want to, that is why it is better to keep them in a save place.

Posted in Computers & Tech / Hardware Workshop
Author: Arbitrary Total-Replies: 195

Mine is bad. And very slow. And all that crap.

Intel Pentium III
128MB
USB 1.1
CD-ROM drive

etc etc

No additions to it. So my computer ends up having a lot of freeze-ups. >_>

Posted in General Discussion / Science & Technology
Author: Quatrux Total-Replies: 192

I am not a religious person, I just like to stay neutral, even though I believe in some kind of a "creator", but creator of what? Definitely not humans, because that in some way is proved by science.. but nevertheless I think that now God is only our imagination, no one has prove he exists, we just believe in something we created our selfs, we even created "love" and "fate".. we created numbers and mathematics, we created ..1010 1000 0001.. we agreed on what we created. So in some way, we are the "creators" but we, the creators do not know who created us, the galaxy, the universe.. so we believe in theories which were created by us..

In some way, I believe that the word God stands for something we don't know, for example in the ancient Greece, we didn't know why lightning appeared, so we created a God of lightning, it is logical, we don't know what is the last number in the mathematics, so we have an object -8 +8 just the letter 8 is horizontal, not vertical. We don't know yet, but everything is changing with time, we know more and more and maybe we one day will reach a such knowledge that we will reach the God and our mission will be over, maybe.. We have a wide imagination and can think of a lot of things.. People used to believe that the World is flat, so we have different theories what kind of form the universe is, but maybe the future people will be laughing from us, because they will know it.

On this subject no one is right, no one is false, it is a lifestyle, if you believe it or not, I can create my own religion and can find people which will believe it, in some way the Church, Christians is a sect having the most members, same for any other religion. But this guy is right in some way, especially people start to believe in God when something bad happens, like you are near death. Humans are not perfect and I think there is nothing perfect.