SISTEM DAN KONVERSI BILANGAN BINER
Sistem bilangan biner atau sistem bilangan basis dua adalah sebuah sistem penulisan angka dengan menggunakan dua simbol yaitu 0 dan 1. Sistem bilangan biner modern ditemukan oleh Gottfried Wilhelm Leibniz pada abad ke-17. Sistem bilangan ini merupakan dasar dari semua sistem bilangan berbasis digital. Dari sistem biner, kita dapat mengkonversinya ke sistem bilangan Oktal atau Hexadesimal. Sistem ini juga dapat kita sebut dengan istilah bit, atau Binary Digit. Pengelompokan biner dalam komputer selalu berjumlah 8, dengan istilah 1 Byte. Dalam istilah komputer, 1 Byte = 8 bit. Kode-kode rancang bangun komputer, seperti ASCII, American Standard Code for Information Interchange menggunakan sistem peng-kode-an 1 Byte.
Bilangan desimal yang dinyatakan sebagai bilangan biner akan berbentuk sebagai berikut:
Desimal Biner (8 bit)
0 0000 0000
1 0000 0001
2 0000 0010
3 0000 0011
4 0000 0100
5 0000 0101
6 0000 0110
7 0000 0111
8 0000 1000
9 0000 1001
10 0000 1010
11 0000 1011
12 0000 1100
13 0000 1101
14 0000 1110
15 0000 1111
16 0001 0000
20=1
21=2
22=4
23=8
24=16
25=32
26=64
Berdasarkan referensi diatas yang mendekati bilangan 10 adalah 8 (23), selanjutnya hasil pengurangan 10-8 = 2 (21) sehingga dapat dijabarkan seperti berikut
10 = (1 x 23) + (0 x 22) + (1 x 21) + (0 x 20).
Dari perhitungan di atas bilangan biner dari 10 adalah 1010 dan dapat juga dengan cara lain yaitu 10 : 2 = 5 sisa 0 (0 akan menjadi angka terakhir dalam bilangan biner), 5(hasil pembagian pertama) : 2 = 2 sisa 1 (1 akan menjadi angka kedua terakhir dalam bilangan biner), 2(hasil pembagian kedua): 2 = 1 sisa 0(0 akan menjadi angka ketiga terakhir dalam bilangan biner), 1 (hasil pembagian ketiga): 2 = 0 sisa 1 (0 akan menjadi angka pertama dalam bilangan biner) karena hasil bagi sudah 0 atau habis, sehingga bilangan biner dari 10 = 1010 atau dengan cara yang singkat 10:2=5(0),5:2=2(1),2:2=1(0),1:2=0(1)sisa hasil bagi dibaca dari belakang menjadi 1010.
PENGKODEAN DATA
• Sebuah karakter data disimpan dalam main memory menempati posisi 1 byte
• Komputer Generasi I, 1 byte terdiri dari 4 bit, menggunakan pengkodean binari BCD (Binary Coded Decimal)
• Komputer Generasi II, 1 byte terdiri dari 6 bit, menggunakan pengkodean binari SBCDIC (Standard Binary Coded Decimal Interchange Code)
• Komputer sekarang, 1 byte terdiri dari 8 bit, menggunakan EBCDIC (Extended Binary Coded Decimal) atau ASCII (American Standard Code for Information Interchange)
• BCD (Binary Coded Decimal)
• Mewakili nilai digit desimal, angka 0 sampai 9
• Banyak kombinasi yang mungkin adalah 24 = 16, tapi yang digunakan 10 kombinasi
• Kode BCD yang orisinal sudah jarang digunakan karena keterbatasan pengkodean
• SBCDIC dan EBCDIC
SBCDIC
• Standard Binary Coded Decimal Interchange Code
• Menggunakan kombinasi 6-bit (binary digit), artinya ada 64 kemungkinan, yaitu 10 kode digit angka, 26 kode huruf alpabet, dan sisanya karakter-karakter khusus yang dipilih
ASCII
• American Standard Code for Information Interchange yang dikembangkan oleh ANSI (American National Standards Institute)
• Kombinasi 7 bit à 128 kemungkinan, yaitu:
26 buah huruf kapital dari A s.d. Z
26 buah huruf kecil dari a s.d. Z
10 digit desimal dari 0 s.d. 9
34 karakter kontrol yang tidak dapat dicetak hanya digunakan untuk informasi status operasi komputer
32 karakter khusus (special characters)
BAHASA PEMOGRAMAN
• Bahasa adalah suatu sistem untuk berkomunikasi
• Bahasa tertulis adalah suatu sistem berkomunikasi dengan menggunakan simbol (huruf) untuk membentuk kata
Dalam ilmu komputer, bahasa manusia disebut bahasa alamiah (natural languages), dimana komputer tidak bisa memahaminya, sehingga diperlukan suatu bahasa komputer
• Level Menengah: Level bahasa gabungan antara intruksi mesin dengan instruksi yang mulai mendekati bahasa manusia berkomunikasi, contoh: bahasa assembler dan bahasa C
PERBANDINGAN LEVEL BAHASA PEMROGRAMAN
Generasi I: Bahasa Mesin
• ENIAC (Electronic Numerical Integrator and Calculator) pada tahun 1945 oleh Mauchly and Eckert.
• Menggunakan kode-kode biner (0 dan 1), dengan basis dasar transistor. “On” = 1, dan kondisi “Off” = 0.
• Rumit, sukar dihafal, dan lama
• Dikembangkan dengan bilangan oktal dan heksadesimal
Generasi II : Low Level Language
• Penyempurnaan dari bahasa mesin
• Bahasa assembly sudah mulai memasukkan unsur kata bahasa Inggris meskipun dalam bentuk singkat
• Bersifat machine dependent
• Penulisan bahasa assembly sudah jauh lebih mudah dibanding dengan bahasa mesin, namun masih terlalu sulit bagi orang awam yang tidak memahami perangkat keras komputer, karena beberapa variabel masih mengacu pada register, alamat memori maupun alamat port I/O.
Generasi III : High Level Language
• 1950, FORTRAN (FORmula TRANslator), yang sudah bersifat machine independent.
• Diikuti bahasa pemrograman aras tinggi spt : BASIC, COBOL, PL/1, PASCAL, ALGOL, PROLOG, C, dan lain-lain.
• Pemrosesan program oleh komputer dalam bahasa aras tinggi ini meliputi:
• Compilation
• Link
• Execution
Generasi IV: Bahasa Deklaratif
• Bahasa pemrograman ini jauh lebih mudah ditulis karena instruksinya sudah sangat mendekati bahasa percakapan sehari-hari
• Contoh: DBASE, SQL (Structured Query Language)
Generasi V : Object-Oriented Language
• Contoh: SIMULA, SmallTalk, Ada, C++, atau Java
DEFINISI PROGRAM DAN PEMROGRAMAN
Program adalah kumpulan instruksi-instruksi tersendiri yang biasanya disebut source code yang dibuat oleh programmer (pembuat program) atau suatu bagian executable dari suatu software
• Pengertian Program Komputer
• Langkah Langkah Membuat Program
Langkah-langkah sistematis dalam pembuatan suatu program, sebagai berikut:
1. Mendefinisikan Permasalahan dan membuat rumusan untuk pemecahan masalah
2. Implementasi (Menulis Program)
3. Kompiling
4. Menguji Coba
MEMBUAT DOKUMENTASI DAN PERSIAPAN UNTUK PRODUKSI
Untuk memudahkan dalam memeriksa kesalahan suatu program ataupun memahami jalannya program, perlu membuat dokumentasi dari program yang dibuat
• Tahap-Tahap Pengembangan Program
• Flowchart atau Diagram Alir
Pengertian:
Flowchart atau diagram alir berfungsi sebagai alat bantu yang berupa simbol–simbol yang saling dihubungkan sehingga dapat menggambarkan alur pikir sebuah program atau permasalahan yang akan diproses dengan progam komputer
Friday, March 19, 2010
Friday, February 12, 2010
Ten tips for better writing on your blog…
1. DO write about what matters to you.
This is the first commandment of blogging. The most successful blogs are written by people who are passionate about their subject matter. When you write about topics that excite you, your writing will communicate a sense of energy that will attract like-minded readers. You'll also be more likely to keep on blogging, and won't abandon your blog after a few days or weeks.
2. DON'T take a too-formal tone.
Blogging is a more informal medium than print, and your writing style should reflect that. Blogging allows you to write in a casual, face-to-face tone, as if you were sitting down for a cup of coffee with your readers. One way to begin to develop your blog "voice" is to read blogs that resonate with you and study the ways in which those bloggers choose words that maintain a professional tone while still being warm and accessible.
3. DO edit yourself.
Hey, it's your blog, right? You can write a 2,000-word essay on what you had for breakfast, or wax eloquent about everything that is wrong with retail customer service. Don't do it. Once you draft your post, read through it for redundancies, irrelevant anecdotes or anything that isn't vital. You might find that you have enough material for 2 or 3 unique posts. Your blog isn't a book; make it lean.
4. DON'T use tired clichés.
A cliché is a phrase that has been coined for so long that it has become boring. An easy way to turn off readers and make them move on to another site is to pepper your posts with clichés like "right as rain" and "easy as pie." Take a minute to prune those phrases out and replace them with something fresh and original.
5. DO spell check your posts before you click "Publish Now."
TypePad offers a spellchecking function that makes it easy for you to have typo-free posts. Whenever you see a red line beneath a word, double check the spelling. Watch out for common misspellings that won't show up on the spellchecker, such as "your" versus "you're," "their" versus "there," and "principle" and "principal."
6. DON'T forget basic principles of good text layout.
Readability is one of the most important aspects of good blog copy. Use line breaks between paragraphs. Use sub-heads, preferably in bold type. Use italics for emphasis. Your goal is to draw the eye and create a smooth sense of flow throughout your post. Make it easy to read!
7. DO use lists. Most blog readers skim copy rather than read it all the way through.
One way to maximize your copy impact is to use lists. Bullet lists or numbered lists call attention to important points, and ensure that readers who are skimming will catch the most vital part of your post.
8. DON'T use the same format in every post.
Mix it up a little! Some might incorporate lists, while others might be more narrative. Some posts might include a lot of images, while others will be more copy-heavy. Don't do the same thing every time.
9. DO create descriptive headlines that let readers know what to expect from your posts.
One of the best things about blogging is that it allows you to be creative. Problem is, what is clever to you might be confusing to someone else. The best way to encourage more people to read your post is to write a compelling post title, and use subheads throughout your post.
10. DON'T sweat it.
Don't let these guidelines keep you from blogging – the most important thing is to keep writing. If you write with passion and conviction, you’ll be able to connect with other people, and your writing will improve every time you post.
This is the first commandment of blogging. The most successful blogs are written by people who are passionate about their subject matter. When you write about topics that excite you, your writing will communicate a sense of energy that will attract like-minded readers. You'll also be more likely to keep on blogging, and won't abandon your blog after a few days or weeks.
2. DON'T take a too-formal tone.
Blogging is a more informal medium than print, and your writing style should reflect that. Blogging allows you to write in a casual, face-to-face tone, as if you were sitting down for a cup of coffee with your readers. One way to begin to develop your blog "voice" is to read blogs that resonate with you and study the ways in which those bloggers choose words that maintain a professional tone while still being warm and accessible.
3. DO edit yourself.
Hey, it's your blog, right? You can write a 2,000-word essay on what you had for breakfast, or wax eloquent about everything that is wrong with retail customer service. Don't do it. Once you draft your post, read through it for redundancies, irrelevant anecdotes or anything that isn't vital. You might find that you have enough material for 2 or 3 unique posts. Your blog isn't a book; make it lean.
4. DON'T use tired clichés.
A cliché is a phrase that has been coined for so long that it has become boring. An easy way to turn off readers and make them move on to another site is to pepper your posts with clichés like "right as rain" and "easy as pie." Take a minute to prune those phrases out and replace them with something fresh and original.
5. DO spell check your posts before you click "Publish Now."
TypePad offers a spellchecking function that makes it easy for you to have typo-free posts. Whenever you see a red line beneath a word, double check the spelling. Watch out for common misspellings that won't show up on the spellchecker, such as "your" versus "you're," "their" versus "there," and "principle" and "principal."
6. DON'T forget basic principles of good text layout.
Readability is one of the most important aspects of good blog copy. Use line breaks between paragraphs. Use sub-heads, preferably in bold type. Use italics for emphasis. Your goal is to draw the eye and create a smooth sense of flow throughout your post. Make it easy to read!
7. DO use lists. Most blog readers skim copy rather than read it all the way through.
One way to maximize your copy impact is to use lists. Bullet lists or numbered lists call attention to important points, and ensure that readers who are skimming will catch the most vital part of your post.
8. DON'T use the same format in every post.
Mix it up a little! Some might incorporate lists, while others might be more narrative. Some posts might include a lot of images, while others will be more copy-heavy. Don't do the same thing every time.
9. DO create descriptive headlines that let readers know what to expect from your posts.
One of the best things about blogging is that it allows you to be creative. Problem is, what is clever to you might be confusing to someone else. The best way to encourage more people to read your post is to write a compelling post title, and use subheads throughout your post.
10. DON'T sweat it.
Don't let these guidelines keep you from blogging – the most important thing is to keep writing. If you write with passion and conviction, you’ll be able to connect with other people, and your writing will improve every time you post.
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