From 2b269055c4222c7ac77e6e4971dbfc84fda26b12 Mon Sep 17 00:00:00 2001 From: Kurt Zeilenga Date: Wed, 15 Nov 2006 19:20:18 +0000 Subject: [PATCH] Clarify that directories are searchable and browsable databases, not just directories optimized for read access. Categorize DNS as a "lookup" service. Give dmoz.org as an example of directory service. --- doc/guide/admin/intro.sdf | 46 +++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 16 deletions(-) diff --git a/doc/guide/admin/intro.sdf b/doc/guide/admin/intro.sdf index 9960d05d5e..a26ac9cc9e 100644 --- a/doc/guide/admin/intro.sdf +++ b/doc/guide/admin/intro.sdf @@ -15,19 +15,25 @@ provided by {{slapd}}(8). H2: What is a directory service? -A directory is a specialized database optimized for reading, browsing -and searching. Directories tend to contain descriptive, attribute-based -information and support sophisticated filtering capabilities. -Directories generally do not support complicated transaction or -roll-back schemes found in database management systems designed -for handling high-volume complex updates. Directory updates are -typically simple all-or-nothing changes, if they are allowed at -all. Directories are tuned to give quick response to high-volume -lookup or search operations. They may have the ability to replicate -information widely in order to increase availability and reliability, -while reducing response time. When directory information is -replicated, temporary inconsistencies between the replicas may be -okay, as long as they get in sync eventually. +A directory is a specialized database specifically designed for +searching and browsing, in additional to supporting basic lookup +and update functions. + +Note: A directory is defined by some as merely a database optimized +for read access. This definition, at best, is overly simplistic. + +Directories tend to contain descriptive, attribute-based information +and support sophisticated filtering capabilities. Directories +generally do not support complicated transaction or roll-back schemes +found in database management systems designed for handling high-volume +complex updates. Directory updates are typically simple all-or-nothing +changes, if they are allowed at all. Directories are generally +tuned to give quick response to high-volume lookup or search +operations. They may have the ability to replicate information +widely in order to increase availability and reliability, while +reducing response time. When directory information is replicated, +temporary inconsistencies between the replicas may be okay, as long +as inconsistencies are resolved in a timely manner. There are many different ways to provide a directory service. Different methods allow different kinds of information to be stored @@ -41,9 +47,17 @@ services are usually {{distributed}}, meaning that the data they contain is spread across many machines, all of which cooperate to provide the directory service. Typically a global service defines a uniform {{namespace}} which gives the same view of the data no -matter where you are in relation to the data itself. The Internet -{{TERM[expand]DNS}} (DNS) is an example of a globally distributed -directory service. +matter where you are in relation to the data itself. + +A web directory, such as provided by the Open Directory Project +<{{URL:http://dmoz.org}}>, is a good example of a directory service. +These services catalog web pages and are specifically designed to +support browsing and searching. + +While some consider the Internet {{TERM[expand]DNS}} (DNS) is an +example of a globally distributed directory service, DNS is not +browsable nor searchable. It is more properly described as a +globaly distributed {{lookup}} service. H2: What is LDAP? -- 2.39.5