A - - #8 bit, Byte, Yutaka Yasuda
bit : データの最小単位 1bit = 最小状態の単位 = 二進一桁 コンピュータ内部は電気配線 配線に電気が通っている いな い だけで処理 状態は2種 二値 二進 動作にうまく対応 二進一桁を配線一本で実現 0と1 二進数 で動作 の実体 1bit = 二進一桁 = 配線一本
Byte : Byte bit 8 1 Byte 0-255 256 255 2Bytes 1 2 1
0, 1 3
ASCII a 61! " # $ % & ' ( ) * +, -. / sp 0 1 2 3 4 5 6 7 8 9 : ; < = >? @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ` a b c d e f g h i j k l m n o p q r s t u v w x y z { } ~ \0 \n 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f \t
画像のデータ表現 絵は画素(Pixel : Picture Element)ごとに分解 一画素ごとに赤 緑 青 (RGB) に 色分解して各色256段階で記録 最大 16,777,216 色 赤 緑 青 229 83 158 242 231 80 155 0 46 動画も簡単にデータ化できますね
400KB JPEG vs GIF JPEG : 40.9KB 34KB GIF : 1.8KB
CD 44KHz, 16bit MP3 CD 1/8 1/15 AAC, ATRAC, WMA 4,3,4,7,7,8,8,5,3,2,2
111,121,122,89,80,82,75. 10,240,22,30,34,80 12,33,45,1123,488 33,38,42,60,32,39,55,80
CPU
1Byte 8bit, 0 255 8bit 4Byte 32bit, 0~4G 9 43 32bit 8Byte 64bit, 0?? 19 64bit 10 4bit 2 15 1111 14 1110 13 1101 12 1100 11 1011 10 1010 9 1001 8 1000 7 0111 6 0110 5 0101 4 0100 3 0011 2 0010 1 0001 0 0000
2 1 1Byte 8bit, 0 255 1Byte 8bit, -128 127 S (sign) S 7bit 10 4bit 2 7 0 111 6 0 110 5 0 101 4 0 100 3 0 011 2 0 010 1 0 001 0 0 000-1 1 111-2 1 110-3 1 101-4 1 100-5 1 011-6 1 010-7 1 001-8 1 000
123.45 1.2345 x 10^2 (^2) (12345) S (sign) (32bit) S 8bit 23bit 10-38 10 38 10 0 2 12345 2 (64bit) S 11bit 52bit 10-308 10 308
123.45 0 10000101 11101101110011001100110 10000101=128+5 1 111011. 01110011001100110 127 6 1 6 1111011 = 123 011100... 0.25 + 0.125 + 0.0625... 123.4499969... 24bit 7 0.1 = 0, 01111011, 10011001100110011001101 0.5 = 0, 01111110, 00000000000000000000000
Microsoft Excel 2004 for Macintosh (N ) 2 N 2 N +1 8 256 257 16 65,536 65,537 32 4,294,967,296 4,294,967,297 64 18,446,744,073,709,600,000 18,446,744,073,709,600,000 48 281,474,976,710,656 281,474,976,710,657 49 562,949,953,421,312 562,949,953,421,313 50 1,125,899,906,842,620 1,125,899,906,842,620 51 2,251,799,813,685,250 2,251,799,813,685,250 4 15 +1
111,121,122,89,80,82,75. 10,240,22,30,34,80 12,33,45,1123,488 33,38,42,60,32,39,55,80
1/2 0/1 CD 9 1 0 0 or 1 1/9
data (8bit) P 0 0 1 1 0 1 0 1 0-1 bit... 1 bit 2 bit CRC Cyclic Redundancy Check
ECC Error Correcting Code 64bit 8bit ECC 1bit 2bit CIRC : CD *ECC Error check and correct memory
CD/CD-R CD / CD-R / ipod / SD ipod
Hardware Hardware Software data media data media
Hardware Software Format data media
Hardware MP3 Format Hardware CD audio Format Hardware MPEG Format MP3 music SD card MP3 CD audio CD CD MPEG2 video DVD DVD
PC : MP3 Format Hardware OS (system software) CD audio Format MPEG Format MP3 music SD card MP3 CD audio CD CD MPEG2 video DVD DVD
Windows Windows Media Player MP3 MPEG Hardware Microsoft Windows MS Word Word fmt. MS Excel Excel fmt. Adobe Reader PDF fmt. MP3 music MPEG2 video Word Excel PDF USB DVD MP3 DVD PDF
Web MP3 Web (Internet Explorer, Firefox, etc.) MPEG Hardware OS (system software) HTML JPEG PDF MP3 music MPEG2 video JPEG PDF Internet ( ) PDF
(generic) (specific)
Case Study HTML5 Google / WebM VP8 On2 Ogg Theora Apple H.264
Google launches open WebM web video format based on VP8 (2010/5/19, Engadget) http://www.engadget.com/2010/05/19/google-launches-open-webm-web-video-format-based-on-vp8/
Case Study HTML5 Google / WebM VP8 On2 Ogg Theora Apple H.264
A - - #11 Internet Yutaka Yasuda
IP (Internet Protocol) IP TCP IP SMTP (Simple Mail Transfer Protocol) HTTP (Hyper Text Transport Protocol)
LAN LAN 61.194.20.172 61.194.20.x 133.101.x.x 133.101.35.108 IP ISP
Server Client Client Client Server Client Client
Web Web Web http://www.kyoto-su.ac.jp/ GET... Server Client
IP www.kyoto-su.ac.jp DNS (Domain Name System) IP
Web DNS IP
Web 1. http://www.kyoto-su.ac.jp/ IP 2. DNS.jp PC 3. DNS DNS IP DNS #2 DNS #2 DNS #1 jp? Web Server
Web 4. DNS #2 ac 5. #2 #3 DNS #3 DNS #2 DNS #1 DNS #3 ac? Web Server Client
Web 6. DNS #3 kyoto-su 7. #3 KSU DNS DNS #3 DNS #2 DNS #1 KSU s DNS KSU DNS kyoto-su? Web Server Client
Web 8. KSU DNS www IP 9. 133.101.120.20 DNS #3 DNS #2 DNS #1 KSU s DNS www 133.101.120.20 Web Server Client
Web 10. 133.101.120.20 Web 11. DNS #3 DNS #2 DNS #1 KSU s DNS GET... 133.101.120.20 Web Server Client
ARPANET TCP/IP IP DNS