Address Classes

Address Classes

In the original Internet routing scheme developed in the 1970s, sites were assigned addresses from one of three classes: Class A, Class B and Class C. The address classes differ in size and number. Class A addresses are the largest, but there are few of them. Class Cs are the smallest, but they are numerous. Classes D and E are also defined, but not used in normal operation.

To say that class-based IP addressing in still used would be true only in the loosest sense. Many addressing designs are still class-based, but an increasing number can only be explained using the more general concept of CIDR, which is backwards compatible with address classes.

Suffice it to say that at one point in time, you could request the Internet NIC to assign you a class A, B or C address. To get the larger class B addresses, you might have to supply some justification, but only the class A was really tough to get. In any case, NIC would set the network bits, or n-bits, to some unique value and inform the local network engineer. It would then be up to the engineer to assign each of his hosts an IP address starting with the assigned n-bits, followed by host bits, or h-bits, to make the address unique.

Internet routing used to work like this: A router receiving an IP packet extracted its Destination Address, which was classified (literally) by examining its first one to four bits. Once the address's class had been determined, it was broken down into network and host bits. Routers ignored the host bits, and only needed to match the network bits to find a route to the network. Once a packet reached its target network, its host field was examined for final delivery.

Summary of IP Address Classes

Class A - 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

• First bit 0; 7 network bits; 24 host bits

• Initial byte: 0 - 127

• 126 Class As exist (0 and 127 are reserved)

• 16,777,214 hosts on each Class A

Class B - 10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh

• First two bits 10; 14 network bits; 16 host bits

• Initial byte: 128 - 191

• 16,384 Class Bs exist

• 65,532 hosts on each Class B

Class C - 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

• First three bits 110; 21 network bits; 8 host bits

• Initial byte: 192 - 223

• 2,097,152 Class Cs exist

• 254 hosts on each Class C

Class D - 1110mmmm mmmmmmmm mmmmmmmm mmmmmmmm

• First four bits 1110; 28 multicast address bits

• Initial byte: 224 - 247

• Class Ds are multicast addresses - see RFC 1112

Class E - 1111rrrr rrrrrrrr rrrrrrrr rrrrrrrr

• First four bits 1111; 28 reserved address bits

• Initial byte: 248 - 255

• Reserved for experimental use

Domain Names

Domain Names

Internet domains form the basis of the common Internet naming scheme. For example, www.cnn.com is a domain name, and cnn.com is a domain.

Domains are structured in the form of an inverted tree. Each branch or leaf on the tree is labeled with an simple alphanumeric string, and a complete domain name is written by stringing all the labels together, separated by periods. Thus, www.cnn.com is a third-level domain name. The root domain is com, the second level label is cnn, and the third level is www. Incidentally, there is no standard way to visually distinguish a branch from a leaf. In fact, the Internet domain system makes no distinction between the two, since branches can have any attributes of a leaf, and leaves can have children added to them and become branches.

The diagram below illustrates the novell.com domain. The interpretation of domain names ending in novell.com is solely at the discretion of Novell. They manage the shaded area of the domain name space.

As documented in RFC 1591, top-level domain names take one of two forms. First, they can be generic domains, all of which are populated by predominately American domains. Alternately, a top-level domain can be a UN two-digit country code, listed in ISO-3166, the most common form for non-American domains.

      Generic Domains                          Country Domains
                                               (partial list)

   com - Commercial                         uk - United Kingdom
   edu - Educational                        fr - France
   org - Non-profit Organizations           de - Germany
   net - Networking Providers               nl - Netherlands
   mil - US Military                        us - United States
   gov - US Government                      au - Australia
   int - International Organizations        ax - Antarctica

To make use of domain names, they must be converted into 32-bit IP Addresses. This is done using the DNS Protocol.

Domain name registrations are handled by InterNIC in North America, RIPE in Europe, and APNIC in Asia. Domain name assignment is completely distinct from IP address assignment

Cryptography

Cryptography

Cryptography, the encoding of messages to render them unreadable by anyone other than their intended recipient(s), is centuries old. The "Caesar Cipher" is so named because it was used by Julius Caesar. With the advent of modern computer technology, many of these older ciphers became trivially crackable using brute-force attacks. Modern cryptography, essential to the security of computer networks, is done with complex algorithms implemented on high speed computer systems. Generally speaking, computer cryptographic tasks can be broken into two general categories: encryption and authentication.

Encryption

Encryption refers to the scrambling of information so that the original message can not be determined by unauthorized recipients. An encryption algorithm is applied to the message, referred to as the plaintext, and a key to produce ciphertext, which ideally appears to be random bits. A decryption algorithm converts the ciphertext back into plaintext, but only if given the correct key. Conventional, or symmetric, algorithms use the same key for both encryption and decryption. Public key algorithms use paired keys, one for encryption and another for decryption.

Authentication

Authentication is the verification of a message's sender. Authentication requires protecting a message so it can not be altered, usually by attaching to it a digital signature. Typically, the signature is formed by computing a hash of the message, which is encrypted using a public key cryptosystem, insuring that nobody without the proper key can generate a valid signature. Note that authentication is different from encryption, since the actual message may be completely unencrypted, and cryptography used only to validate the identify of the creator.

Often, much attention is given to the algorithm, and little paid to the key. In fact, just as with login passwords, cryptographic systems are only as secure as their keys, making key management a critical and oft neglected concern. Certificates have emerged as a clever way of managing large scale key distribution.

RSA Laboratory's Cryptography FAQ is an excellent reference source on cryptography.

\begin{soapbox}

It's become clear in recent years that strong cryptographic protection is essential to any computer security system. Whether it be protecting login passwords from packet sniffers, defeating trojan horse attacks, or ensuring that a user's files are unreadable even if a hard drive is stolen, cryptography is a critical component in a secure computer architecture. Many of the widely publicized breakins and attacks could have been prevented if stronger cryptographic controls were in place.

For example, Jon Boone's proposal for Integrity Checked Linux would augment the Linux kernel to require every privileged program to pass a cryptographic check before it would be allowed to execute. Since the check would be made using a public key system, and the private key used to sign the programs could be stored off-line, this would immediately defeat any attempt by a hacker to modify system binaries. A similar idea is used by Tripwire, though without kernel support it is both more portable and more vulnerable.

There's been a serious stumbling block in the way of these efforts, though. Adding cryptography to the Linux kernel (or any other piece of software) would make it export-controlled, and that's not a step Linus Torvalds has been willing to take. In fact, the U.S. Federal Government's insistence on restricting the distribution of cryptographic software has probably been one of the biggest barriers to improved computer security.

In recent years, there have been signs of improvement. The U.S. government has relaxed its regulations on exporting cryptographic software. Some cryptographic support has been added to the Linux kernel by the FreeS/WAN project. However, other countries, such as France, continue to impose controls on the use and distribution of strong crypto. I'd be nice to get at least one message across on this point:

Weak cryptography means weak security!

\end{soapbox}

Network History

Internet History

1969 - Birth of a Network

The Internet as we know it today, in the mid-1990s, traces it origins back to a Defense Department project in 1969. The subject of the project was wartime digital communications. At that time the telephone system was about the only theater-scale communications system in use. A major problem had been identified in its design - its dependence on switching stations that could be targeted during an attack. Would it be possible to design a network that could quickly reroute digital traffic around failed nodes? A possible solution had been identified in theory. That was to build a "web" of datagram network, called an "catenet", and use dynamic routing protocols to constantly adjust the flow of traffic through the catenet. The Defense Advanced Research Projects Agency (DARPA) launched the DARPA Internet Program.

1970s - Infancy

DARPA Internet, largely the plaything of academic and military researchers, spent more than a decade in relative obscurity. As Vietnam, Watergate, the Oil Crisis, and the Iranian Hostage Crisis rolled over the nation, several Internet research teams proceeded through a gradual evolution of protocols. In 1975, DARPA declared the project a success and handed its management over to the Defense Communications Agency. Several of today's key protocols (including IP and TCP) were stable by 1980, and adopted throughout ARPANET by 1983.

Mid 1980s - The Research Net

Let's outline key features, circa-1983, of what was then called ARPANET. A small computer was a PDP-11/45, and a PDP-11/45 does not fit on your desk. Some sites had a hundred computers attached to the Internet. Most had a dozen or so, probably with something like a VAX doing most of the work - mail, news, EGP routing. Users did their work using DEC VT-100 terminals. FORTRAN was the word of the day. Few companies had Internet access, relying instead on SNA and IBM mainframes. Rather, the Internet community was dominated by universities and military research sites. It's most popular service was the rapid email it made possible with distant colleagues. In August 1983, there were 562 registered ARPANET hosts (RFC 1296).

UNIX deserves at least an honorable mention, since almost all the initial Internet protocols were developed first for UNIX, largely due to the availability of kernel source (for a price) and the relative ease of implementation (relative to things like VMS or MVS). The University of California at Berkeley (UCB) deserves special mention, because their Computer Science Research Group (CSRG) developed the BSD variants of AT&T's UNIX operating system. BSD UNIX and its derivatives would become the most common Internet programming platform.

Many key features of the Internet were already in place, including the IP and TCP protocols. ARPANET was fundamentally unreliable in nature, as the Internet is still today. This principle of unreliable delivery means that the Internet only makes a best-effort attempt to deliver packets. The network can drop a packet without any notification to sender or receiver. Remember, the Internet was designed for military survivability. The software running on either end must be prepared to recognize data loss, retransmitting data as often as necessary to achieve its ultimate delivery.

Late 1980s - The PC Revolution

Driven largely by the development of the PC and LAN technology, subnetting was standardized in 1985 when RFC 950 was released. LAN technology made the idea of a "catenet" feasible - an internetwork of networks. Subnetting opened the possibilities of interconnecting LANs with WANs.

The National Science Foundation (NSF) started the Supercomputer Centers program in 1986. Until then, supercomputers such as Crays were largely the playthings of large, well-funded universities and military research centers. NSF's idea was to make supercomputer resources available to those of more modest means by constructing five supercomputer centers around the country and building a network linking them with potential users. NSF decided to base their network on the Internet protocols, and NSFNET was born. For the next decade, NSFNET would be the core of the U.S. Internet, until its privatization and ultimate retirement in 1995.

Domain naming was stable by 1987 when RFC 1034 was released. Until then, hostnames were mapped to IP address using static tables, but the Internet's exponential growth had made this practice infeasible.

In the late 1980s, important advances related poor network performance with poor TCP performance, and a string of papers by the likes of Nagle and Van Jacobson (RFC 896, RFC 1072, RFC 1144, RFC 1323) present key insights into TCP performance.

The 1987 Internet Worm was the largest security failure in the history of the Internet. More information can be found in RFC 1135. All things considered, it could happen again.

Early 1990s - Address Exhaustion and the Web

In the early 90s, the first address exhaustion crisis hit the Internet technical community. The present solution, CIDR, will sustain the Internet for a few more years by making more efficient use of IP's existing 32-bit address space. For a more lasting solution, IETF is looking at IPv6 and its 128-bit address space, but CIDR is here to stay.

Crisis aside, the World Wide Web (WWW) has been one of Internet's most exciting recent developments. The idea of hypertext has been around for more than a decade, but in 1989 a team at the European Center for Particle Research (CERN) in Switzerland developed a set of protocols for transferring hypertext via the Internet. In the early 1990s it was enhanced by a team at the National Center for Supercomputing Applications (NCSA) at the University of Illinois - one of NSF's supercomputer centers. The result was NCSA Mosaic, a graphical, point-and-click hypertext browser that made Internet easy. The resulting explosion in "Web sites" drove the Internet into the public eye.

Mid 1990s - The New Internet

Of at least as much interest as Internet's technical progress in the 1990s has been its sociological progress. It has already become part of the national vocabulary, and seems headed for even greater prominence. It has been accepted by the business community, with a resulting explosion of service providers, consultants, books, and TV coverage. It has given birth to the Free Software Movement.

The Free Software Movement owes much to bulletin board systems, but really came into its own on the Internet, due to a combination of forces. The public nature of the Internet's early funding ensured that much of its networking software was non-proprietary. The emergence of anonymous FTP sites provided a distribution mechanism that almost anyone could use. Network newsgroups and mailing lists offered an open communication medium. Last but not least were individualists like Richard Stallman, who wrote EMACS, launched the GNU Project and founded the Free Software Foundation. In the 1990s, Linus Torvalds wrote Linux, the popular (and free) UNIX clone operating system.

\begin{soapbox}

The explosion of capitalist conservatism, combined with a growing awareness of Internet's business value, has led to major changes in the Internet community. Many of them have not been for the good.

First, there seems to be a growing departure from Internet's history of open protocols, published as RFCs. Many new protocols are being developed in an increasingly proprietary manner. IGRP, a trademark of Cisco Systems, has the dubious distinction as the most successful proprietary Internet routing protocol, capable only of operation between Cisco routers. Other protocols, such as BGP, are published as RFCs, but with important operational details omitted. The notoriously mis-named Open Software Foundation has introduced a whole suite of "open" protocols whose specifications are available - for a price - and not on the net. I am forced to wonder: 1) why do we need a new RPC? and 2) why won't OSF tell us how it works?

People forget that businesses have tried to run digital communications networks in the past. IBM and DEC both developed proprietary networking schemes that only ran on their hardware. Several information providers did very well for themselves in the 80s, including LEXIS/NEXIS, Dialog, and Dow Jones. Public data networks were constructed by companies like Tymnet and run into every major US city. CompuServe and others built large bulletin board-like systems. Many of these services still offer a quality and depth of coverage unparalleled on the Internet (examine Dialog if you are skeptical of this claim). But none of them offered nudie GIFs that anyone could download. None of them let you read through the RFCs and then write a Perl script to tweak the one little thing you needed to adjust. None of them gave birth to a Free Software Movement. None of them caught people's imagination.

The very existence of the Free Software Movement is part of the Internet saga, because free software would not exist without the net. "Movements" tend to arise when progress offers us new freedoms and we find new ways to explore and, sometimes, to exploit them. The Free Software Movement has offered what would be unimaginable when the Internet was formed - games, editors, windowing systems, compilers, networking software, and even entire operating systems available for anyone who wants them, without licensing fees, with complete source code, and all you need is Internet access. It also offers challenges, forcing us to ask what changes are needed in our society to support these new freedoms that have touched so many people. And it offers chances at exploitation, from the businesses using free software development platforms for commercial code, to the Internet Worm and the security risks of open systems.

People wonder whether progress is better served through government funding or private industry. The Internet defies the popular wisdom of "business is better". Both business and government tried to build large data communication networks in the 1980s. Business depended on good market decisions; the government researchers based their system on openness, imagination and freedom. Business failed; Internet succeeded. Our reward has been its commercialization.

\end{soapbox}

For the next few years, the Internet will almost certainly be content-driven. Although new protocols are always under development, we have barely begun to explore the potential of just the existing ones. Chief among these is the World Wide Web, with its potential for simple on-line access to almost any information imaginable. Yet even as the Internet intrudes into society, remember that over the last two decades "The Net" has developed a culture of its own, one that may collide with society's. Already business is making its pitch to dominate the Internet. Already Congress has deemed it necessary to regulate the Web. The big questions loom unanswered: How will society change the Internet... and how will the Internet change society?

Networking

Documenting my home network

(Alex Barnett's blog -The blog of Alex Barnett)

I have no idea why I have bothered to diagram and document

my home network, but since I have, here it is...

Buffalo LinkStation Network Storage Center

My most recent acquisition is Buffalo LinkStation Network Storage Center, a 120GB drive connected by Ethernet to the Netgear wireless router. It has a USB 2.0 interface that will connect to a backup drive (not got yet) with a built-in print server. I'm using SyncToy to synchronize files across the network, with the Network drive acting as the master. I also considered the Iomega Network 160GB Hard Drive, but the built-in print server on the Buffalo just pipped it for me, even though it had 40GB less than the Iogema for the same price.

Netgear Wireless Router

The Netgear wireless router is a 54Mbps WRG614 v5, 802.11b/g, has a built-in firewall and has turned out to be very reliable. It has 4 wireless devices registered (2 laptops, the wireless media player and Xbox), and four Ethernet connected devices (the DSL modem, network drive, desktop pc and VoIP phone adapter/router).

Vonage VoIP Phone Adapter

This LinkSys RT31P2 phone adapter is connected by Ethernet to the wireless routers and has 2 phone adapters. One of the phone adapters connects to a 5.8GHz cordless phone base. The phone adapter / router was provided by our VoIP landline provider, Vonage. We need the landline so Kate can run her UK business from here, otherwise I wouldn't bother with a landline - my mobile does what I need. It's been surprisingly reliable and trouble-free.

Toshiba Laptop, Tablet PC and Compaq Presario Desktop

The Tecra M2 and Portege Tablet PC are running wireless 802.11 g and b respectively. Ideally I'd like to upgrade the Tablet's wireless card to g standard. The Compaq Presario desktop (old model) is connected to the wireless router by Ethernet. Each have the Buffalo Network Storage drive and printer mapped. I have SyncToy for Windows XP Professional installed on each of these machines to synchronize with the network drive, each running a daily sync Scheduled Task. The Tecra M2 and Desktop each also have a Netgear Media Server instance installed that talks to the Netgear MP 101 media player when running. The desktop has become the 'familiy pc' that our son can use without destroying stuff - it also runs the guest accounts for friends who need to check email, surf, etc. Considering upgrading hardware to run Windows XP Media Center.

HTC C500 Smartphone (known as Audiovox in US)

What would I do without my SPV C500 Smartphone? (known as Audiovox SMT5600 in the US) Runs Windows Mobile, and use ActiveSync 3.8 on the Tecra via USB 2.0 to sync to Outlook and copy camera phone pics / video over to the Tecra. I don't use the Exchange server sync - I think it would drive me mad knowing I'd had a gazillion unopened work emails I'd need to constantly check.

Packard Bell Digital Camera

The DSC-400 is a cheap and cheerful 4.07 Megapixel digital camera I bought in the UK with USB 2.0 port to import pics stored on network drive. The pics are sync'd from the network drive to the 2 laptops using SyncToy.

Xbox

Have 2 Xbox's, one is in the main room using Xbox wireless adapter to nail suckers on Rainbow Six 3. Is also our DVD player. The other Xbox in the office is from the UK which I brought over as we had a ton of UK DVDs for our son (this part sucks - regional DVD is such pain - totally anti-consumer...beyond belief!). Can't wait for the Xbox 360!

Netgear MP101, Media Player

Netgear MP101 is wireless 802.11g music media player. Of all the devices connected to the network, this one gives me the most trouble, specifically the failure rate of it being assigned an IP when booting. I often have to reboot three or four times before it has an IP address. Once it has this it runs fine, connecting to one of the Netgear Media Servers on either the Tecra or the desktop. One additional annoyance is that if left idle for half an hour or so it loses its IP address, requiring another 3-4 reboots. The initial installation is not for the faint hearted, nor user-friendly. That said, I love it once up and running.

Filed under: Tech

Selamat Tahun Baru 1429 H

Doa Awal Tahun & Doa Akhir Tahun

Barangsiapa yang membaca doa awal tahun ini, insya Allah dirinya akan terpelihara daripada gangguan dan godaan syaitan di sepanjang tahun tersebut.

Doa Awal Tahun:

Maksudnya: Allah SWT berselawat ke atas penghulu kami Muhammad SAW, ahli keluarga dan sahabat-sahabat baginda dan kesejahteraan ke atas mereka. Wahai Tuhan, Engkaulah yang kekal abadi, yang qadim. yang awal dan ke atas kelebihanMu yang besar dan kemurahanMu yang melimpah dan ini adalah tahun baru yang telah muncul di hadapan kami. Kami memohon pemeliharaan dariMu di sepanjang tahun ini dari syaitan dan pembantu-pembantunya dan tentera-tenteranya dan juga pertolongan terhadap diri yang diperintahkan melakukan kejahatan dan usaha yang mendekatkanku kepadaMu Wahai Tuhan Yang Maha Agung dan Maha Mulia. Wahai Tuhan Yang Maha pengasih dari mereka yang mengasihi dan Allah berselawat ke atas penghulu kami Muhammad. Nabi yang ummi dan ke atas ahli keluarga dan sahabat-sahabatnya dan kesejahteraan ke atas mereka.

Barangsiapa yang membaca doa akhir tahun ini, maka syaitan
akan berkata:
"Hampalah kami di sepanjang tahun ini".

Doa Akhir Tahun:

Maksudnya:

Allah SWT berselawat ke atas penghulu kami Muhammad SAW, ahli keluarga dan sahabat-sahabat baginda dan kesejahteraan ke atas mereka.

Wahai Tuhan, apa yang telah aku lakukan dalam tahun ini daripada perkara-perkara yang Engkau tegah daripada aku melakukannya dan aku belum bertaubat daripadanya. Sedangkan Engkau tidak redha dan tidak melupakannya. Dan aku telah melakukannya di dalam keadaan di mana Engkau berupaya untuk menghukumku, tetapi Engkau mengilhamkanku dengan taubat selepas keberanianku melakukan dosa-dosa itu semuanya. Sesungguhnya aku memohon keampunanMu, maka ampunilah aku. Dan tidaklah aku melakukan yang demikian daripada apa yang Engkau redhainya dan Engkau menjanjikanku dengan pahala atas yang sedemikian itu. Maka aku memohon kepadaMu.

Wahai Tuhan! Wahai yang Maha Pemurah! Wahai Yang Maha Agung dan wahai Yang Maha Mulia agar Engkau menerima taubat itu dariku dan janganlah Engkau menghampakan harapanku kepadaMu Wahai Yang Maha Pemurah. Dan Allah berselawat ke atas penghulu kami Muhammad, ke atas ahli keluarga dan sahabat-sahabatnya dan mengurniakan kesejahteraan ke atas mereka.

Mantainance PC

Merawat PC: 20 Kit Tool Praktis dan Mudah

Untungnya, dengan sedikit upaya dan tool yang tepat, pemeliharaan dan perbaikan PC menjadi mudah untuk kebanyakan orang. Dan mendapatkan tool yang tepat tidak harus dibayar dengan tangan dan kaki; beberapa sudah Anda miliki, dan lainnya murah. Inilah tool yang kami rekomendasikan agar Anda miliki.

Tool yang Dapat Anda Pilih

Kecuali merawat banyak PC, Anda tidak memerlukan kit tool PC yang gaya itu yang harganya lebih dari US$ 50 (walaupun Standard Computer Tool Kit seharga US$ 15 buatan Belkin merupakan alternatif bagus yang murah). Malahan, daftar hardware yang harus Anda miliki tidaklah panjang.

>>TIP Obeng: Anda hanya butuh dua obeng kecil: satu dengan kepala pipih standar, dan yang satu lagi dengan kepala kembang. Biasanya kurang dari enam inci panjangnya -- dan pastikan semuanya tidak bermagnet.

>>TIP Penjepit: Penjepit mungil dengan cengkeraman yang bagus tak ternilai harganya untuk memasang dan melepas jumper dan untuk mendapatkan kembali sekrup yang hilang. Penjepit dengan ujung datar lebih berguna dibanding yang ujung runcing.

>>TIP Senter: Bahkan di ruangan yang terang-benderang, bisa saja sulit melihat kabel-kabel kecil dan konektor di bagian dalam casing PC Anda.

>>TIP Wadah komponen: Wadah kecil--lebih disukai yang berpenutup-- penting untuk menyimpan sekrup dan jumper. Cangkir plastik atau botol obat lama sudah memadai.

>>TIP Tang berujung runcing: Tang kecil berujung runcing berguna untuk merenggut bagian-bagian dan menekuk kawat dan potongan logam.

>>TIP Botol semprot: Jaga agar saluran ventilasi dan interior PC bebas debu untuk mencegah kelebihan panas. Sejauh ini botol semprot merupakan cara termudah untuk melakukannya. Botol semprot tersedia di banyak toko komputer dan elektronik dengan harga kurang dari US$ 10.

>>TIP Peranti gelang antistatik: Satu sentakan listrik statik yang bergerak antara tubuh Anda dan PC dapat memanggang sirkuit mesin. Bila Anda menambah atau melepas hardware, atau melakukan pekerjaan apa pun di bagian dalam casing PC, kenakan peranti gelang antistatik. Salah satu ujung terhubung ke pergelangan Anda, dan ujung lainnya terhubung ke tanah. Ini tersedia di toko komputer dan elektronik dengan harga kurang dari US$ 10.

>>TIP Pengencang mur dan tool khusus lain: Banyak kit tool komputer mencakupkan pengencang mur, pelepas chip, dan tool khusus lainnya. Kami anggap hal ini merupakan pemerasan habis-habisan terhadap rata-rata pengguna sebab obeng dan penjepit sudah mencukupi untuk sebagian besar pekerjaan.

Tool Yang Telah Anda Miliki

Windows menyediakan banyak utiliti dan wizard berguna untuk troubleshooting dan perawatan PC. Banyak di antaranya bisa diakses dari menu System Tools: Klik Start*Programs*Accessories*System Tools (istilah dan path yang sesuai bervariasi bergantung versi Windows Anda).

>>TIP ScanDisk: Seperti yang tergambar pada namanya, ScanDisk memeriksa hard disk terhadap fragmen file yang keliru letak dan daerah kerusakan fisik. Periksa hard drive Anda secara teratur dengan ScanDisk. Kenaikan mendadak pada jumlah program yang mengalami error bisa berarti kerusakan hard disk.

Windows XP tidak punya utiliti ScanDisk. Untuk memeriksa suatu drive di XP, klik-kanan di Explorer, pilih Properties, pilih tab Tools, dan klik Check Now pada `Error- checking`. Anda akan diberitahu bahwa utiliti itu butuh hak eksklusif ke beberapa file Windows dalam disk. Bila Windows menanyakan apakah Anda ingin melakukan pemeriksaan saat restart berikut, klik Yes kemudian OK.

>>TIP Disk Defragmenter: Defragmen hard drive secara teratur untuk menjaganya berjalan lebih cepat dan untuk meningkatkan peluang Anda memulihkan data jika drive tersebut mengalami crash.

>>TIP System Monitor: Program kecil yang luar biasa ini membantu Anda melacak banyak jenis parameter kinerja. Anda dapat melihat grafik real- time yang menampilkan available RAM, virtual memory, CPU usage, dan statistik lainnya. System Monitor terutama bagus untuk melacak sumber problem memori dan mengidentifikasi program mana yang paling membuat stres sistem Anda. (Di Windows XP, Anda bisa menemukan System Monitor dengan memilih Start*Control Panel*Administrative Tools*Performance*System Monitor.)

>>TIP System Information: Utiliti ini merupakan jembatan ke beberapa tool troubleshooting paling kuat di Windows. Pada Windows 9x, Anda akan mendapati System File Checker, Registry Checker, dan System Configuration Utility pada menu Tools di System Information. Di XP, tool di System Information mencakupkan Network Diagnostics dan System Restore.

>>TIP Manual, driver, dan software: Selamatkan segala sesuatunya! Anda mungkin dapat mengatasi problem PC dengan mengetahui satu setting utama atau nomor model, atau dengan menginstall ulang program. Manual yang dicetak mungkin menjadi satu-satunya sumber nomor telepon bantuan teknis Anda. Jangan mengira Anda dapat mendownload saja sebarang file yang mungkin Anda butuhkan kapan saja dari Internet: Sebuah file di tangan berharga dibanding dua di Web.

>>TIP Windows Resource Kit: Anda tidak perlu menghabiskan US$ 50 atau lebih untuk buku referensi Windows seukuran buku telepon itu. Anda hanya perlu berkonsultasi dengan CD Windows 9x. Di tools\reskit\setup folder, Anda akan mendapati salinan online Windows Resource Kit dari Microsoft (versi cetak harganya US$ 70). Pergilah ke Microsoft TechNet ( www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/winxppro/reskit/prork_overview.asp?frame=true) untuk Windows XP Professional Resource Kit.

Tool yang Bisa Anda Gunakan Secara Gratis
Berikut ini beberapa gratisan diagnosa dan perawatan favorit.

>>TIP #1-TuffTest-Lite: Program ini memastikan bahwa semua komponen hardware PC Anda berfungsi dengan benar. Karena booting dan berjalan dari floppy-nya sendiri, program ini melampaui keterbatasan pengujian program-program diagnosis yang berjalan dari dalam sistem operasi yang kompleks seperti Windows. Versi gratis program itu punya fungsi yang lebih sedikit dibanding US$ 10 #1-TuffTest (menguji hanya 8MB RAM, misalnya).

>>TIP DisplayMate: Pertajam image monitor Anda dengan versi demo utiliti ini. Versi lengkap harganya US$ 79, namun demo mempunyai enam pola uji dan instruksi mengenai cara menggunakannya (lihat Gambar 2).

>>TIP Situs-situs Web bermanfaat: Drivers HeadQuarters di www.drivershq.com merupakan tempat yang bagus untuk menemukan update atau driver peranti yang hilang. Dan kunjungi www.utilitygeek.com untuk mencari utiliti free dan shareware lain untuk merawat dan mendiagnosa PC Anda.

Tool yang Berharga untuk Dibeli

>>TIP Norton SystemWorks 2002: Dengan US$ 70, bundel utiliti ini tidak murah, namun berisi barang bagus. Komponen yang paling penting adalah Norton Utilities, koleksi klasik program Windows dan hard-disk (lihat Gambar 3). Ketika banyak fungsi Norton Utilities dapat direplikasi dengan utiliti gratis atau murah seperti yang tercatat di atas, paket all-in-one yang menyenangkan dan ekstra seperti penjadwalan otomatis membuat Norton SystemWorks sebanding dengan harganya.

>>TIP PartitionMagic 7: Ada banyak cara mudah dan sulit untuk membuat, menghapus, dan mengubah ukuran partisi hard-drive. Program seharga US$ 70 dari PowerQuest ini merupakan yang termudah. FDISK di Windows merupakan salah satu dari beberapa alternatif pemartisi yang aktif jika Anda punya banyak waktu dan sedikit uang. Namun jika Anda butuh mendapatkan kelengkapan kerja yang cepat dan simpel, interface fasih dan operasi cepat pada PartitionMagic membuatnya menjadi pembelian yang bijak.

>>TIP Drive Image 5: Tool PowerQuest ini akan menyelamatkan Anda dari kesalahan yang Anda buat ketika menggunakan tool diagnosa PC lainnya. Drive Image 5 menyalin dan mengkompresi seluruh drive--atau lebih akuratnya, seluruh partisi--menjadi sebuah file yang dapat Anda pulihkan dengan mudah. Tempatkan file backup-nya di partisi lain, di hard disk lain, atau (di versi terbaru ini) ke disk-disk CD-R/RW. Drive Image menyalin regular files, hidden files, system files, dan boot sector sehingga Anda dapat memulihkan salinan pekerjan seluruh partisi, termasuk OS yang dapat dibooting, aplikasi, dan data.

Board Jelek?

Anda duduk, lalu menyalakan PC... dan tidak terjadi apa-apa: tiada cahaya, tiada suara, tiada aksi. Perlukah Anda menghabiskan ratusan dollar untuk motherboard baru, atau lebih kurang untuk power supply baru? ATX Power Supply Tester dari PC Power and Cooling bisa memberikan jawaban cepat dan akurat. Tool praktis seharga US$ 10 ini terhubung ke kabel motherboard dari sebarang power supply kompatibel ATX 2.x dan akan menyala jika power supply bekerja dengan benar. Anda dapat mengetahui lebih jauh tentangnya di www.pcpowerandcooling.com.