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Showing posts from December 28, 2018

コネクションレス型通信

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コネクションレス型通信 とは、 Datagram (データグラム)とも呼ばれる、経路確保などの事前のやり取り(コネクションの確立)無しに、データ送信を開始するパケット通信の方式である。 TCP/IPにおけるUDPで用いられている。 特徴 Virtual Callと比較して、以下の点が特徴である。 通信プロトコルが単純になる。 宛先情報などパケットのヘッダが大きくなり、通信効率が悪い。 経路が予め確保されていないため、交換処理が複雑になる。 上位プロトコルで、受信パケットの順序の整列、未着・破損パケットの再送信、などを行う必要がある。 関連項目 コネクション型通信 - 経路確保などの事前のやり取り(コネクションの確立を行ってからデーター送信を開始するパケット通信、TCP/IPにおけるTCP この項目は、コンピュータに関連した 書きかけの項目 です。この項目を加筆・訂正などしてくださる協力者を求めています(PJ:コンピュータ/P:コンピュータ)。 This page is only for reference, If you need detailed information, please check here

Printer Detected As USB Composite Device - With Warning

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2 My parents have started to have a problem printing from their PC, and naturally as the go-to IT expert, I have been drafted in to have a look! Before they went on holiday a month ago, it was apparently working fine. On their return last week, they were unable to print. I believe windows updates were installed on their return. I have removed the printer, an HP C4400, and uninstalled all related software, then re-installed the software and drivers. When re-adding the printer, the HP install software hangs at "detecting printer". In device manager, I see a "USB Composite Device" appearing, however this shows a yellow warning, with a message stating that the composite device drivers are missing or corrupt. I have tried adding a different model of printer, with the same result - it appears as a composite USB device, with errors. I have also tried connecting the printer to another PC, and it installed and worked perfectly. Any suggestions? How can I repair

getElementsByClassName returns “undefined”

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-3 var element = document.getElementsByClassName('nav-download')[0]; console.log(element); The class nav-download returns undefined for me in console.log. I wanted to know how to handle this. javascript share | improve this question edited Nov 12 at 19:25 montrealist 2,958 7 35 49 asked Nov 12 at 19:17 João Filipe 1 1 Can you include the HTML as well – Sushanth -- Nov 12 at 19:19 2 Please only use English on StackOverflow. – connexo Nov 12 at 19:23 add a comment  |  -3 var element = document.getElementsByClassName('nav-download')[0]; console.log(element); The class nav-download returns undefined for me in console.log. I wanted to know how to handle this. javascript share | improve this question edited Nov 12 at 19:25 montrealist 2,958 7 35 49 asked Nov 12 at 19:17 João Filipe 1 1 Can you include the HTML as wel