All About Computer

New Fiture Of Smart Phones

Smart Phones have gained in popularity of the last few years. They have cellular accessories built into the phone. There a now a number of smart phones available to purchase. But what is a smart phone exactly? That is a fair question that comes with no definitive answer. What can be agreed on in the industry are a few key things. A smart phone will exceed the features and capabilities of a normal mobile device, needing less cellular accessories like Motorola accessories, making it more than a phone. They typically have a full organization system on the phone, with calendars, alarms, reminders and address books, among others. They also have complete email capabilities and a QWERTY keypad or a touch screen for typing. Now that we have a basic idea of what a Smart Phone is, let's look at a few of the most popular phones available.

The iPhone 3GS
The iPhone 3GS - This has all the amazing capabilities of the iPhone 3G but with more common cell phone features such as multimedia messaging and voice dialing. It has a longer battery life than the previous model and the multimedia features are astounding. This is faster than the old iPhone making it a must have, upgrade for many users. It may have the most built-in cellular accessories to date.

The RIM BlackBerry Bold 9700
The RIM BlackBerry Bold 9700 - This smart phone has a sleek design that includes an optical trackpad, a 3.5mm headphone jack, and a nice display. It is 3G capable and offers Wi-Fi with UMA support, Bluetooth, and GPS. It also has a faster processor and can update to BlackBerry OS 5.0. This phone gives T-Mobile its first 3G BlackBerry and improves on its predecessor with a sleeker design and more power. It also is compatible with many Motorola accessories.
The Palm Pre - This phone has unparalleled multitasking capabilities and notification systems. It features a display with multi-touch functionality as well as a strong web browser and multimedia integration. The Pre offers good call quality and wireless options such as 3G, Wi-Fi, Bluetooth, and GPS. The Palm Pre offers gadget lovers and phone users well-integrated features. This phone shows a solid OS that not only rivals the competition but also sets a new standard in the way smart phones handle tasks and manage information.
While a definition of what a smart phone is can't be agreed upon, it is obvious they are the phones that go above and beyond the average mobile devices capabilities. If multitasking is normal in one's life, or if organization is must then a smart phone is ideal. There are a number of choices and surely there is a smart phone that works with each person's unique needs.

While computers today are generally cheaper than models sold years ago, they still represent a major investment. Quality new computers can cost anywhere from $500 - $1500, depending upon capabilities. Clearly, it is a purchase that deserves your full attention and thought. Speaking of thought, have you ever considered buying a used or refurbished computer? These computers can represent a major savings to you, without loss of performance. However, there are some things you should know before looking into these alternatives to new computers. In this article, we'll discuss some tips in buying used and refurbished computers.

This Is some tips in buying used and refurbished computers :

The first thing to consider when buying used and refurbished computers is the brand. While there are many different companies that specialize in selling used computers, it might be best to go with a reputable brand name. The reasons are two-fold. First, you can be sure that the parts used in manufacturing are of a high quality. Second, you will also be able to secure some type of warranty, which may not be offered by other dealers.

The next tip in buying used and refurbished computers is to make sure that that you receive the proper software documents and licenses. Often times people try to pass off stolen computers as "used", so it is important to request the paperwork upfront. It is also important to have this software in case you need to do any type of system restore or back-up.

It is also important that you try any refurbished computer before you buy. Most reputable dealers will allow you to use the computer for a short period of time to check out before committing to purchase. What are a few of the things you should be looking for? Make sure that all installed programs boot up and perform correctly. Do a thorough check of all graphics, video, and sound drivers and also make sure other accessories work properly (mouse, monitor, keyboard, etc.). Lastly, be sure to check all CD and disk drives to make sure they open and close correctly.


Another thing to consider when buying a used or refurbished computer is the support option. Does the company you want to buy from have ample support staff available? And are the hours convenient with your own schedule? If a business does not offer support for the system you are considering, it is best to move on to another choice.

Lastly, make sure that you are safe if shopping online for your used or refurbished computer. The internet can pose many dangers, so protect your personal information on any site that you choose to do business with. A quality site will have some type of encryption service in place to keep your financial transaction private.

We hope that these tips in buying used and refurbished computers will help you make a more informed shopping decision. In addition to the tips mentioned in this article, using common sense will help ensure that you receive the best used computer for your needs, at a terrific value.

32-bit dan 64-bit mengacu pada arsitektur processor.
Processor 32-bit artinya register2 nya (unit penyimpanan data terkecil di dalamnya) berukuran 32 bit.
Processor 64-bit artinya register2 nya berukuran 64 bit.

( Register2 inilah yang digunakan untuk melakukan macam2 operasi. Misalnya c = a + b, maka register "eax" akan me-load nilai dari "a" (di memory), kemudian pada register "eax" ditambahkan nilai dari "b", lalu "eax" ditulis ke memory pada posisi variabel "c" )

Pengaruh ukuran register terhadap kecepatan:

Setiap proses baca/tulis dari memory (disebut dengan load/store) membaca/menulis informasi sebesar ukuran register; maka register 64-bit potensial membaca/menulis memory 2x kecepatan register 32-bit.
Tapi ini teoretis saja, karena kenyataannya prosesor juga menghabiskan waktu untuk melakukan hal-hal lain selain load/store, seperti pemrosesan matematis, vector-processing, dll.

Pengaruh ukuran register terhadap presisi:

Secara simplistik: Makin panjang register, makin banyak angka di-belakang-koma yang bisa dihitung secara akurat.
Sebagai gambaran: Misalkan resolusi bilangan real pada 32-bit adalah 0.0001, maka resolusi bilangan real pada 64-bit bisa mencapai 0.0000001 (jadi jauh lebih presisi).

Pengaruh ukuran register terhadap ukuran memori:

Salah satu dari sekian banyak register adalah "addressing register". Addressing register (atau registers, kalau lebih dari satu) adalah register yang memiliki fungsi 'menunjuk' ke alamat tertentu dalam memory. Jangkauan (range) penunjukan ini disebut dengan istilah memory space.
Pada arsitektur 32-bit, addressing registers mampu 'menunjuk' posisi memory dari 0 s/d 4'294'967'295 (4 GiB - 1). Inilah yang mengakibatkan muncul "batasan 4 GiB" pada sistem berbasis arsitektur 32-bit.
Pada arsitektur 64-bit, addressing registers mampu 'menunjuk' posisi memory dari 0 s/d 18'446'744'073'709'551'615 (16 EiB - 1). Seperti kita lihat, tidak ada lagi 'batasan 4 GiB' pada sistem berbasis arsitektur 64-bit.

Pengaruh ukuran register terhadap dataset:

"Dataset" adalah istilah untuk 'seperangkat data yang di-load ke dalam memory untuk diproses dan (optionally) ditulis kembali ke hard disk'.
Sistem 32-bit terbatas pada dataset sebesar (2^32)-1, atau (4 GiB - 1). Mengingat sebagian memory harus digunakan untuk OS dan program database ybs, maka biasanya dataset nya hanya sebesar 1-2 GiB saja.
Artinya, sebuah database yang berukuran, katakanlah, 20 GiB (tidak asing dalam konteks perusahaan besar), harus diproses 10~20x.
Sistem 64-bit tidak memiliki batasan di atas. Dia dapat me-load dataset sebesar ketersediaan memory. Artinya, database 20 GiB di atas dapat di-load seluruhnya (asal memory mencukupi), diproses dalam sekali jalan saja.

Agar kita dapat memperoleh keunggulan sistem 64-bit, maka baik software dan hardware harus mendukung.
Software 32-bit jalan di hardware 64-bit tidak bisa memanfaatkan kelebihan arsitektur 64-bit. (Software hanya akan menggunakan 32-bit saja dari 64-bit yang tersedia; 32-bit sisanya tidak dikenali) ==> disebut mode 32-bit.
Sebaliknya, software 64-bit tidak bisa jalan di hardware 32-bit karena kebutuhannya akan lebar register 64-bit tidak bisa dipenuhi.

Windows XP 32-bit dan Windows Vista 32-bit adalah 2 sistem operasi yang masih beroperasi di mode 32-bit.
Windows XP 64-bit dan Windows Vista 64-bit adalah 2 sistem operasi yang mampu beroperasi di mode 64-bit.

AMD64 adalah terobosan (breakthrough) AMD dalam dunia processor x86.

Dahulu hingga prosesor Pentium 3, Intel bersikukuh menggunakan hanya arsitektur 32-bit pada processor x86. Intel menghabiskan uang jutaan dollar untuk mengembangkan arsitektur 64-bit yang samasekali baru (artinya: tidak kompatibel dengan dunia x86) dalam bentuk Intel ITANIUM.

AMD kemudian mengembangkan instruction set (dan arsitektur) dari processor x86 yang dibuatnya (AthlonXP) sehingga lahirlah Athlon64: Processor x86 yang memiliki arsitektur 64-bit.

Instruction set yang diperluas ini disebut AMD64 oleh AMD. Intel terpaksa melakukan cross-license, dan menggunakan instruction set tersebut juga (tapi dengan nama EMT64, bukan AMD64. Biasalah, masalah corporate pride...)

Saya tidak yakin dengan Mac OS X.
Tetapi Linux memiliki versi 32-bit dan versi 64-bit.
Contoh, Ubuntu yang ada di ftp://dl2.foss-id.web.id/iso/ubuntu/releases/hardy/
Ada versi AMD64 (64-bit) dan ada versi i386 (32-bit)

Kelebihan dan kekurangan?

Kita sudah melihat kelebihan dari arsitektur 64-bit.

Sekarang kekurangannya:

Banyak Software 32-bit yang tidak bisa jalan di arsitektur 64-bit, khususnya driver.

Mengapa bisa begitu?

Komputer adalah benda yang sangat kompleks. Untuk bisa berguna bagi manusia, komputer perlu melakukan apa yang disebut "Input/Output" (I/O). Contoh I/O adalah kirim/terima data via LAN, kirim gambar ke Monitor via VGA Card, dll.

Nah, semua tindakan I/O membutuhkan buffer. Sebagai contoh, kita kenal "memory VGA" pada VGA Card; itu sebetulnya adalah buffer untuk membantu VGA Card menampilkan gambar di monitor.

Masalahnya, agar I/O bisa berlangsung dengan mulus dan cepat, 'buffer' ini perlu mendapatkan alamat. Dan alamat ini di ambil dari memory space. Hal ini terjadi meskipun komponen pelaksana I/O ini memiliki buffernya sendiri (contoh: VGA Card terbaru dari nVidia / ATI biasanya punya minimal 256 MiB RAM pada card nya). Tetap saja memori pada card tersebut akan dipetakan ke memory space.

Agar tidak bentrok dengan Sistem Operasi, yang biasanya di-load ke dalam memory 'rendah' (Bottom Memory = memory dengan alamat kecil), maka biasanya pemetaan buffer ini dilakukan di memory 'tinggi' (Top Memory = memory dengan alamat besar, atau dihitung mundur dari alamat memori terbesar (2^32)-1)

Catatan: Ini juga alasan yang menyebabkan RAM komputer kalau terpasang 4 GiB hanya akan bisa dipakai Max 3,25 GiB (atau kalau untung 3,5 GiB), ada yang 'hilang' karena 'tertutupi' oleh buffer dari komponen I/O.

Nah, pada arsitektur 64-bit, hal yang sama pun dilakukan: Buffer untuk I/O dipetakan ke Top Memory. Masalahnya, Top Memory pada arsitektur 64-bit jelas terletak pada posisi yang berbeda dengan Top Memory pada arsitektur 32-bit.

Driver adalah korban yang paling jelas; mereka berusaha mengakses Top Memory 32-bit, padahal lokasi buffer tidak di situ. Akibatnya: Crash.

Software2 lain yang juga coba-coba mengakses Top Memory secara langsung akan mengalami crash juga.

Lucunya, banyak game 32-bit yang malah jalan dengan tanpa masalah di sistem 64-bit; hal ini karena mereka tidak berusaha mengakses Top Memory secara langsung, melainkan meminta bantuan Microsoft DirectX Layer untuk mengakses fitur dari sebuah VGA Card.

- 128 bits is a common key size for symmetric ciphers in cryptography. It is also the size of Globally Unique Identifier and IPv6 address.
- 128-bit processors could become prevalent when 16 exbibytes of addressable memory is no longer enough (128-bit processors would allow memory addressing for 340,282,366,920,938,463,463,374,607,431,768,211,456 bytes (~340.3 undecillion bytes or 281,474,976,710,656 yobibytes ). However, physical limits make such large amounts of memory currently impossible, given that amount greatly exceeds the total data stored on Earth today.
- Quadruple precision (128-bit) floating point number can store qword (64-bit) fixed point number or integer accurately without losing precision. Notice that since the 8087 (1980), x86 architecture supports 80bits float-points that store and process accurately 64bits integers
- Sony's Playstation 2 CPU Emotion Engine is advertised as a 128 bit processor. It has 128-bit SIMD registers, like many processors, but is only a 32-bit processor in the traditional sense as it can only use 32-bit memory addresses.
- The AS/400 virtual instruction set defines all pointers as 128-bit. This gets translated to the hardware's real instruction set as required, allowing the underlying hardware to change without needing to recompile the software. Past hardware was 32-bit CISC, while current hardware is 64-bit PowerPC. Because pointers are defined to be 128-bit, future hardware may be 128-bit without software incompatibility.
- Larger bit widths are also commonly seen on the memory interface of graphics processing units, including 128-bit, with some bus widths reaching 512-bits long.
- Increasing the word size can speed up multiple precision math libraries. Applications include cryptography.
- Large word sizes can increase the feasibility of using certain very fast data structures (consider representing a set by having one bit per possible set element). wikipedia

According to Tanenbaum, the operating system developed very rapidly, which can be divided into four generations:

1. First generation (1945-1955)
The first generation is the early development of electronic computing systems as a substitute for mechanical computing system, it caused people to calculate the speed of humans is limited and very easy to make a faux pas, mistakes and even mistakes. In this generation there is no operating system, the computer system is instructed to do directly.

2. Second Generation (1955-1965)

The second generation introduced a Batch Processing System, the Job is done in a series, then executed berurutan.Pada this generation computer systems not equipped with operating systems, but some of the existing operating system functions, for example, is the operating system function FMS and IBSYS.

3. Third Generation (1965-1980)

In this generation the development of operating systems developed to serve many users at once, where users communicate via an interactive on-line terminal to the computer, the operating system into a multi-user (many users at once using gus) and multi-programming (programs serving many very good).

4. Fourth Generation (Post 1980)

Today, the operating system used for computer networks where users aware of the computers that are connected to each other. At this time our users have also been reassured by the Graphical User Interface is a computer interface based graphics are very comfortable, at this period also began the era of computing where computing-computing spread is no longer centered on one point, but split in many computer so that the performance achieved better.

Operating System Services

A good operating system according to Tanenbaum should have the following services: program development, program execution, accessing the I / O Device, controlled access to the file system access, detection and provision of feedback on errors, and accounting.

Making the program is operating system provides facilities and services to help the programmers to write programs; Program execution which means The instructions and data must be loaded into main memory, the device-parangkat input / output and file must be in-initialization, and the source- existing resources should be prepared, all that should be handled by the operating system; Access to I / O Device, which means that the Operating System has to take over a number of complicated instructions and control signals annoying to programmers be able to think simple and the device can operate; Access control to the file which means that provides protection mechanisms for controlling access to the file to the file; Access to means of accessing the system are used together (shared system); function accesses must provide protection against a number of resources and data from the user can not be distorted as well as resolving conflicts in the struggle for resource- power; Detection and giving feedback on errors, ie if it appears the problems appeared on a computer system, the operating system must provide feedback that describes the error that occurred and its impact on running applications; and Accounting, which means a good Operating System collects statistical data using a variety of sources -power and monitor the performance parameters.