Do it Yourself

The Hardware Hunt

Only after a thorough understanding of how a computer works and boots will you be ready to shop for components and a respective operating system (OS). The hardware (HW) and OS go together because the final OS that you want on your computer often determines the type of HW that you will want to choose.
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The Hardware Hunt

The Hardware Hunt

Only after a thorough understanding of how a computer works and boots will you be ready to shop for components and a respective operating system (OS). The hardware (HW) and OS go together because the final OS that you want on your computer often determines the type of HW that you will want to choose. For example, certain motherboards and CPUs traditionally accompany a PC, whereas others enable a Macintosh. Matching components with an OS has become less important with more modern systems, but if you are considering the self-assembly of a system, which may use older, cheaper parts, then, you will want all HW to match the OS.

Disclaimer and Legal Issues

Like many of the websites, which I have used as reference material, I will make a disclaimer of my own. Assembling your own system has many advantages – it can be customized, faster, cheaper, and easier to repair (since if you put it together yourself, then you know how it works). One disadvantage is that such a system is not under any warranty as a whole (although individual parts may be covered). Therefore, although I have researched the material to follow, I cannot guarantee the complete effectiveness of any self-assembled system. This is true even if you are using new, original components; even more so if you have decided to assemble disposed scraps into a working system.

Furthermore, while reading material from different sites, I have discovered that there are sometimes legal issues when assembling a system. Although, as long as you pay for the HW and OS that you use, you are generally permitted to install and configure it yourself, there may be instances where you need to be careful. For example, it may be illegal to install Mac OS onto a computer with PC components. Be especially careful if you plan to sell the finished product or use it as part of an office network. The article below provides you some food for thought:

http://forums.macrumors.com/archive/index.php/t-230.html

Less (May Be) More

Below is a list of some, though not all, of the issues to consider when assembling a system from scratch.

• What will you use it for? – A computer for which you use Word and Excel and surf the net doesn't require the same power as one on which you create highly sophisticated graphics and animation. Bear this in mind when you choose components.
• What is your budget? – In many cases, you don't need the newest CPU and RAM, cheaper, older, and more established components might be the better choice.
• Parts' availability – The final OS you want to install obviously determines which types of HW you will need. Less obvious, will be the part's availability and cost. This especially holds true if you are assembling an older system. Some parts may be discontinued or simply hard to find.
• Physical style/size of computer – Do you want a desktop or a laptop? What kind of case do you want (more important than you think)? Even if you choose a traditional desktop, how compactly do you want the HW to fit together?
• Compatibility – The Wikipedia site (http://en.wikipedia.org/wiki/Homebuilt_computer) defines three types of self-assembled systems:
• Those assembled from an official kit will be the most compatible and most likely to work effectively, yet they offer the least amount of flexibility. For example, if you're looking for a laptop, try the following link:

http://www.zipzoomfly.com/NBmicro/BIYConfig.html?ppc_cid=ConOLrLapQ208_607944_RZ

• Barebones kits contain just the essentials – a case with a power supply, the motherboard, RAM (memory), CPU (processor), and a fan to keep the CPU cool. You can supplement these with many other components. (See the first article in the "Do it Yourself" column. Below is an example of a G4 Macintosh system.

http://www.macopz.com/buildamac/

• A scavenged or cannibalized system is created from spare parts on the street or in the junkyard. These can be surprisingly effective. My friend and I once made a complete Windows 98 system from old parts in the trash.

Any system that you assemble from scratch may have compatibility issues among HW components and/or between the HW and OS. If you are new at this hacking stuff, try to use a kit, or be prepared to invest the time and patience to make it work.

And Now….the OS, Please

There are so many types of operating systems or platforms. Just like HW, an OS should ideally meet your individual computer needs. Bear in mind that not all OSs contain a GUI (graphical user interface). Wikipedia has a chart that compares the major OSs (http://en.wikipedia.org/wiki/Comparison_of_operating_systems). We will mention some of the more popular and well-known operating systems, which a home user would be likely to install on a desktop for local usage:

OS Name

Explanation

Windows (Microsoft)

(Windows 98, ME, NT, 2000, XP, Vista)

Probably the most popular and widely distributed system, Windows was originally based on the DOS command line system. The newer versions, such as XP and Vista, do not require a DOS base at all and are more robust and stable. Windows offers the most compatibility with the most widely available software, but it may be sluggish for applications that require large amounts of memory such as graphics.

It traditionally has run on IBM and IBM clone systems (such as Intel or competitor processors).

Mac OS (Apple)

(Classic [8-9], Tiger, Panther, Leopard [10.x .x and beyond])

The original primary competitor to Windows in the home market, Mac OS used to be popular in schools and universities. It has made a comeback in recent years, thanks to its Mac OS 10.x series, which can run on an Intel processor.

Although it has consistently grabbed not more than 10 % of the market, making the search for compatible software a problem, many people believe the Mac to be a much more stable system, less prone to freezes and slowdowns. Mac has always been preferred by graphic designers for its stability.

While the Classic version required a RISC (Motorola) processor, the newer versions can be installed on an Intel processor.

Linux (open source)

(Mandrake, Ubunto)

The inspiration for this open source OS (meaning the code can be legally modified by the user) came from more complex and proprietary operating systems, such as Unix (AT&T/Novell) and BSD.

Linux in its various versions offers the advantage of installation on both Windows and Mac based HW. Many people prefer it to Windows for its stability, and compatible SW, such as Open Office, is increasingly available. The downside is that you have to be technically savvy to use it regularly, and you may have to partition your hard drive in order to install it.

Solaris (Sun Microsystems)

(exists in both open and closed versions)

The open version is based on the Sun original closed version. Solaris like Linux is Unix based. It can currently only be installed on Intel based machines.

Next time: We will check out parts' prices for various configurations. Stay tuned!

Giving your Computer the Boot

Giving your Computer the Boot

By this, I don't mean kicking your computer when it freezes or fails to respond! Booting is the initial process that happens when you turn on or power on your computer. The term was coined by comparing the start of a computer with getting dressed.

Correction:    Sorry, I forgot to mention in last month's table a very important component – the power supply. It changes your household current into energy necessary for your computer to run.

What happens every morning just after you get dressed, yet before you're ready to leave the house? Why you put your shoes or boots on, of course! Similarly, the booting of a computer is the last step before a computer is ready to interact with the user – after it is dressed with hardware, but before it's operational.

Last month we discussed the primary categories of hardware and their purpose. Granted, it was an overwhelming list, but there is a method in my madness. In order to know what occurs during booting, you must first be familiar with hardware components as well as what they do.

Booting is essentially a two-step process that consists of two primary steps. The IML or Initial Machine Load followed by the IPL (Initial Program Load). Briefly, the IML loads the hardware, while the IPL loads the software. These two processes normally flow seamlessly together during the entire boot process, unless there is a problem in one of the steps. In that case, you will get an error message describing the problem. The diagram below illustrates the hierarchy in how these processes operate (bottom to top). The IML and IPL overlap with the processes in the diagram, as follows:

Process Name
(bottom to top)

Description

P.O.S.T.

In the Power On Self Test, the power supply checks the electrical current levels to make sure they are sufficient for all of the basic system components – CPU and motherboard.

ROM-B.I.O.S.

(Read Only Memory-Basic Input Output System) Also known as, Firmware, ROM-B.I.O.S. is a set of initial boot instructions that are implanted into the ROM chip on the motherboard.

Boot Loader

During this phase, your computer reads code instructions that identify all partitions on the hard drive and specifically the boot partition – where in your operating system the boot process starts.

O.S.

The Operating System performs three initial actions:

1.   Loads kernel HW and registry information.

2.   Configures all HW.

3.   Searches for additional SW drivers that run other HW devices.

Log On

The Operating System loads the log on and security SW that prompts you for a user profile and password. After this is complete, the OS will run the main file management system. (Desktop)

The source for the above and some of the below material is http://209.85.129.132/search?q=cache:kSOpvQRPOukJ:www.adrc.com/ckr/windows_bootup_process.html+study+guide+bootup+process&hl=en&strip=1

I will now describe the procedure for each of these mega-processes. I urge you to refer to the table in last month's article, http://elephant.org.il/do_it_yourself/, so as not to get lost in the shuffle. Keep in mind that I will not describe every process – for that you can go to Wikipedia.

The IML (also called a pre-booting sequence or P.O.S.T [Power on Self Test])

1. When you turn on the computer (power on), the power supply (see note above) sends current to the motherboard and the CPU. The power supply will continue to send current as long as the computer is on.
2. If these machine components are working properly, the computer emits a beep (in PCs) or another type of sound (in Macs) indicating that the current is sufficient for the rest of the IML. The CPU now initiates the ROM-BIOS.
3. P.O.S.T. continues to perform additional checks on the system, such as:
   • Whether the boot is from a previously off system (cold) or a reboot using the OS (warm).
   • If there are peripheral (read external) devices on the system such as a printer.
   • How much memory RAM is installed on the system.
4. The CPU then searches for the CMOS chip on the motherboard along with any necessary switches or jumpers necessary to assign system resources for this session. These can vary depending on a combination of the motherboard, chips set thereon, and the OS. Different systems will perform their own diagnostic tests.
5. The system now tries to load the hardware devices that match these diagnostics. For example, in a PC it will search for the bootup device (either the old floppy drive or more likely the hard drive; we will see in latter articles that you can configure these priorities).
6. The system, as directed by the CPU, finds the boot code instructions for this bootup device (Master Boot Record for PCs). It copies these instructions into the RAM, and runs them.
7. After running this code successfully, the system searches for the boot partition(s) on the hard drive. These are the sections on the hard drive reserved for booting the computer alone. They must be distinguished from other partitions on the drive for OS to load correctly. A bootup menu displays on the screen offering a choice of more than one OS whenever an additional OS has been installed.

This last step (see the Boot Loader process in the table and chart above)
overlaps with the IPL.

The IPL

1. System files continue to operate and pass on information from the IML. The system begins searching for then loading the kernels and registry information of the OS.
2. The OS collects and configures all devices that have been installed.
3. The OS searches for any hardware profiles and loads the software drives necessary to control these.
4. The OS loads the log on and security files that prompt you for verification such as a password.

Next time: If you truly understood all of the above – more power to you! This information will help tremendously as we look, both for choice parts for your computer as well as get into the types of configurations required to put it all together.