Difference between Object cache and output cache

Question

I came across couple of questions in exam dumps of 70 - 667 but bit confused if someone can explain me difference between output cache and object cache in few lines and possible scenarios we use them in please.

Answer 1

Object cache:

What Object cache does is stores metadata about SharePoint Server objects (like SPWeb, SPSite, SPList, etc.) on the WFEs. When a page is rendered, if there is data that needs to be retrieved through these objects, the SQL Server will not be hit. Features of SharePoint that uses Object cache are publishing, content query web part, navigation, search query box and metadata navigation. There are only few things you can do about this type of cache - set size.

Content cache:

• BLOB cache - used to cache JavaScript, CSS, images files, and large rich media files. Should be used when pages are visited frequently
• Page output cache - can be used only with publishing pages

Summary

Object cache is something what is done automatically. You have to handle content cache manually.

source: http://www.c-sharpcorner.com/Forums/Thread/182474/caching-in-sharepoint-2010.aspx

http://msdn.microsoft.com/en-us/library/aa622758.aspx

http://blogs.msdn.com/b/kunal_mukherjee/archive/2011/01/10/caching-in-share-point-2010-best-practice.aspx

Answer 2

Object cache - metadata, WP queries of external sources, search boxes, quick launch, breadcrumb

Default is on

Configurable through GUI or web.config per each SC

BLOB cache - binary large objects like images or CSS files, stored on WFE disks

Default is off

Configurable through GUI or web.config

Page (output) cache - for whole pages to load them faster for next user with the same rights

Default (for publishing pages) is on

Configurable through GUI (page atributes) or web.config

Office web app cache - XAML queries, images inside documents and so on

Default is on

Configurable through PowerSell, has its own SC (one per web app)

... luccio is right, I just like images :o)