'Computer'에 해당되는 글 568건

  1. 2008.03.01 Device Context by 알 수 없는 사용자
  2. 2008.02.27 AON by 알 수 없는 사용자
  3. 2008.02.19 Link Aggregation Control Protocol by 알 수 없는 사용자
  4. 2008.02.03 새로 설치한 ubuntu에서 자꾸 한글 입력이 안된다. by 언제나19 2
  5. 2008.01.14 같은 LAN 상에 놓여 있는데 PING조차 되지 않을 때 임시방편 by 알 수 없는 사용자
  6. 2008.01.03 IGMP Parameters by 알 수 없는 사용자
  7. 2008.01.01 시작 프로그램 삭제 by 알 수 없는 사용자
  8. 2007.12.21 Marshalling by 알 수 없는 사용자
  9. 2007.12.21 Maven by 알 수 없는 사용자
  10. 2007.12.20 Regular expression by 알 수 없는 사용자

Device Context

Computer/Terms 2008. 3. 1. 09:25

A data structure in Windows programming that is used to define the attributes of text and images that are output to the screen or printer. The device context (DC) is maintained by GDI. A DC, which is a handle to the structure, is obtained before output is written and released after the elements have been written. See GDI.

Reference:
http://www.pcmag.com/encyclopedia_term/0,2542,t=device+context&i=41198,00.asp
Posted by 알 수 없는 사용자
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AON

Computer/Network 2008. 2. 27. 15:42

관련 뉴스들:
http://www.dt.co.kr/contents.htm?article_no=2007013002010151693001, 광가입자망 시장 AON 두각 (하나로ㆍKT 수도권 단지 구축, 수동형보다 경제성 좋아 선호)
http://www.zdnet.co.kr/news/network/etc/0,39031057,39141726,00.htm, 광가입자망 장비시장「AON 기술」급부상 (PON의 절반가격…기능은 100Mbps급 제공)
- 통방융합, 유무선 통합 등을 지원할 광가입자망(FTTH) 장비시장에 경제성을 앞세운 AON(능동형 광네트워크) 기술이 새롭게 급부상하고 있다.

Posted by 알 수 없는 사용자
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The Link Aggregation Control Protocol (LACP) is a computer networking term and is part of IEEE specification 802.3ad that allows bundling several physical ports together to form a single logical channel. LACP allows a network switch to negotiate an automatic bundle by sending LACP packets to the peer. LACP is a protocol implementation in OSI layer 2 which controls through which physical links the traffic will be routed.

Advantages
- Increases bandwidth
- Failover when link status fails on a port.

Practical notes
Several links can be bundled into a single logical link, enabling:
- higher bandwidth connections
- enhanced bandwidth granularity
- load sharing
- fault tolerance protection

The user may aggregate ports into link-aggregation port groups. These groups are treated as individual logical ports. Each group is composed of ports with the same speed, set to full-duplex operation.

The group is represented by a logical Aggregator which offers a standard IEEE 802.3 MAC service interface. An Aggregator can therefore be considered to be a logical MAC, bound to one or more ports.

A single, individual MAC address is associated with each Aggregator.


LACP (802.3ad) for Gigabit Interfaces Feature Overview
The LACP (802.3ad) for Gigabit Interfaces feature bundles individual Gigabit Ethernet links into a single logical link that provides the aggregate bandwidth of up to 4 physical links. A Cisco 10000 series router supports a maximum of 4 Gigabit Ethernet bundled ports per port channel and a maximum of 64 Gigabit Ethernet port channels per chassis.

All LAN ports on a port channel must be the same speed and must all be configured as either Layer 2 or Layer 3 LAN ports. If a segment within a port channel fails, traffic previously carried over the failed link switches to the remaining segments within the port channel. Inbound broadcast and multicast packets on one segment in a port channel are blocked from returning on any other segment of the port channel.

References:
http://en.wikipedia.org/wiki/Link_Aggregation_Control_Protocol
http://www.cisco.com/en/US/docs/ios/12_2sb/feature/guide/gigeth.html#wp1078429

Posted by 알 수 없는 사용자
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한글 입력이 안돼서 한참을 해맸다.
nabi도 설치해보고, 어쩌고.
scim 설정도 여러 번 봐꿔봤다.

진짜 문제는 scim이 실행 안되고 있었던 거였다. 맙소사.
시스템트레이에 키보드 모양 scim이 없었다.
우선은 시작 프로그램에 등록할 줄 몰라서, terminal에서
scim&
을 실행시키고 한글을 입력한다.

그런데, 이후에 가끔은 아예 아무 입력도 안되는 현상이 발생했다.
특히, firefox에서 그런 현상이 발생할 때, 모든 firefox 창을 다 닫고, 다시 열면 키보드 입력이 가능해진다.
어떤 때는 탐색기(?)에서도 그런 문제가 발생하는데, 한번 문제가 발생하면, 파일 이름도 바꿀 수 없고, 탐색기 창에서는 아예 키보드를 쓸 수가 없다.
scim을 종료시켰다가 다시 실행시키면 다시 괜찮아진다.

근본적인 문제가 뭘까 -_-
Posted by 언제나19
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같은 LAN 상에 놓여 있고

케이블에 이상이 없는데도 PING조차 되지 않을 때는 ARP 테이블을 확인해본다.

ARP 테이블을 확인하기 위해서는 윈도우, 리눅스 공통으로

다음과 같이 할 수 있다.

arp -a


ARP 테이블을 확인하여 해당 노드의 MAC 주소가 나오지 않는다면,

수동으로 MAC 주소를 넣어줄 수 있다.

윈도우에서는 다음과 같이 할 수 있다.

arp -s 172.18.90.105 00-90-A3-01-07-04


리눅스에서는 다음과 같이 할 수 있다.

arp -s 172.18.50.117 00:13:8f:42:b9:4d


양쪽 노드에 수동으로 MAC 주소를 넣었는데도 되지 않는다면?

필자도 모르겠다 ㅋ

네트워크 상태가 회복되었다면,

수동으로 넣어준 MAC 주소를 삭제해준다.

윈도우에서는 다음과 같이 할 수 있다.

arp -d 172.18.90.105

리눅스에서는 다음과 같이 할 수 있다.

arp -d 172.18.50.117
Posted by 알 수 없는 사용자
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IGMP Parameters

Computer/Network 2008. 1. 3. 11:46

Robustness Variable
The robustness variable is a way of indicating how susceptible the subnet is to lost packets. IGMP can recover from robustness variable minus 1 lost IGMP packets. You can also click the scroll arrows to select a new setting. The robustness variable should be set to a value of 2 or greater. The default robustness variable value is 2.

Query Interval
The query interval is the amount of time in seconds between IGMP General Query messages sent by the router (if the router is the querier on this subnet). The default query interval is 125 seconds.

Query Response Interval
The query response interval is the maximum amount of time in seconds that the IGMP router waits to receive a response to a General Query message. The query response interval is the Maximum Response Time field in the IGMP v2 Host Membership Query message header. The default query response interval is 10 seconds and must be less than the query interval.

Last Member Query Interval
The last member query interval is the amount of time in seconds that the IGMP router waits to receive a response to a Group-Specific Query message. The last member query interval is also the amount of time in seconds between successive Group-Specific Query messages. The default last member query interval is 1 second.

Startup Query Interval
The startup query interval is the amount of time in seconds between successive General Query messages sent by a querier during startup. The default startup query interval is one-fourth of the value for the query interval.

Startup Query Count
The startup query count is the number of general query messages sent at startup. The default startup query count is 2.

Last Member Query Count
The last member query count is the number of Group-Specific Query messages sent before the router assumes that there are no members of the host group being queried on this interface. The default last member query count is 2.

Enable Automatic Recalculation of Defaults
Specifies whether the values in startup query interval, startup query count, and last member query count are calculated automatically based on the following:

• The startup query interval is one-fourth of the value for the query interval.
 
• The startup query count is the same value as the robustness variable.
 
• The last member query count is the same value as the robustness variable.
 
Group Membership Interval
The group membership interval is the number of seconds that must pass before a multicast router determines that there are no more members of a host group on a subnet. The group membership interval is calculated as the (robustness variable) * (query interval) + (query response interval). The group membership interval is a calculated value and is not configurable.

Other Querier Present Interval
The other querier present interval is the number of seconds that must pass before a multicast router determines that there is no other multicast router that takes precedence as the querier. The other querier present interval is the robustness variable multiplied by the query interval plus the query response interval divided by two. The other querier present interval is a calculated value and is not configurable.

Reference:
http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/intwork/inaf_mul_nuid.mspx?pf=true

Posted by 알 수 없는 사용자
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윈도우에 프로그램을 설치하다보면

의도하지 않게 많은 시작 프로그램이 등록되어

부팅이 느려진다.

이 때, 간단히 등록된 시작 프로그램을 삭제함으로써

부팅 속도를 향상시킬 수 있다.

등록된 시작 프로그램을 삭제하기 위해서는 msconfig 명령을 사용한다.

명령이 실행되면 GUI 화면으로 쉽게 설정이 가능하다.
Posted by 알 수 없는 사용자
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Marshalling

Computer/Terms 2007. 12. 21. 15:51

Marshalling (also known as serialization) is the process of transforming the memory representation of an object to a data format suitable for storage or transmission. It is typically used when data must be moved between different parts of a computer program or from one program to another.

The opposite, or reverse, of Marshalling is called Unmarshalling (also known as deserialization).
- Marshalling is heavily used within Microsoft's Component Object Model (COM), where it is necessary for transporting data between processes and between apartments. The conversion between an unmanaged type and a CLR type, as in the P/Invoke process used in the .NET Framework, is also an example of an action that requires marshalling to take place.
- Additionally, Marshalling is used extensively within scripts and applications that utilize the XPCOM technologies provided within the Mozilla Application Framework. The Mozilla Firefox Browser is a popular application built with this framework, that additionally allows scripting languages to utilize XPCOM through Cross-Platform Connect (XPConnect).

The terms "marshalling" and "serialization" are not synonymous.
- To "marshal" an object means to record its state and codebase(s) in such a way that when the marshalled object is "unmarshalled," a copy of the original object is obtained, possibly by automatically loading the class definitions of the object. You can marshal any object that is serializable or remote. Marshalling is like serialization, except marshalling also records codebases. Marshalling is different from serialization in that marshalling treats remote objects specially.
- To "serialize" an object means to convert its state into a byte stream in such a way that the byte stream can be converted back into a copy of the object.

Reference:
http://en.wikipedia.org/wiki/Marshalling
Posted by 알 수 없는 사용자
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Maven

Computer/Tools 2007. 12. 21. 11:48

Maven is a software project management and comprehension tool. Based on the concept of a project object model (POM), Maven can manage a project's build, reporting and documentation from a central piece of information.



Comments:
JiBX 관련 글을 읽다가 Maven에 대한 이야기를 보고 표시를 해둔다.

소프트웨어 프로젝트 관리 도구로서 많이 사용되는 모양이다.

시간이 날 때 익혀둬야지!

사용해본 분이 있다면, comment를 부탁합니다 :-)



Reference:
http://maven.apache.org/index.html
Posted by 알 수 없는 사용자
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Regular expression

Computer/Terms 2007. 12. 20. 20:37

In computing, a regular expression is a string that is used to describe or match a set of strings, according to certain syntax rules.

Regular expressions are used by many text editors, utilities, and programming languages to search and manipulate text based on patterns. For example, Perl and Tcl have a powerful regular expression engine built directly into their syntax. Several utilities provided by Unix distributions—including the editor ed and the filter grep—were the first to popularize the concept of regular expressions. "Regular expression" is often shortened to regex or regexp (singular), or regexes, regexps, or regexen (plural). Some authors distinguish between regular expression and abbreviated forms such as regex, restricting the former to true regular expressions, which describe regular languages, while using the latter for any regular expression-like pattern, including those that describe languages that are not regular. As only some authors observe this distinction, it is not safe to rely upon it.

As an example of the syntax, the regular expression \bex can be used to search for all instances of the string "ex" that occur at word boundaries (signified by the \b). Thus in the string, "Texts for experts," \bex matches the "ex" in "experts," but not in "Texts" (because the "ex" occurs inside the word there and not immediately after a word boundary).

Many modern computing systems provide wildcard characters in matching filenames from a file system. This is a core capability of many command-line shells and is also known as globbing. Wildcards differ from regular expressions in that they generally only express very restrictive forms of alternation.


Reference;
http://en.wikipedia.org/wiki/Regular_expression

Posted by 알 수 없는 사용자
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