An OCW Installer for Sakai using OKI v3 OSIDs

Mark J. Norton

Nolaria Consulting

July 2008

Overview

– Open Courseware– IMS Common Cartridges– OKI v3 Initiative– Design Challenges– The Installer Application

Sponsorship

• This work was sponsored by contributions from:– The Hewlett Foundation– C( )SL at Utah State University– Office of Educational Innovation and Technology

at MIT

Objective

• Create a web application that:– Installs OCW packages formatted as IMC

Common Cartridges.– Uses the v3 OSIDs for portability– Implements the Filing OSID on Sakai.

Before we get into the details of the project, let’s have a quick look

at OCW, IMS-CC, and OKI.

Open Courseware

and many others …

Open Courseware

• The point of open courseware is to create and distribute free educational material organized as courses.

• These are usually derived from actual course descriptions, syllabus, notes, slides, videos, and other support materials vetted to protect intellectual property rights.

The OCW Movement

• Over 200 organizations worldwide are involved with creating and distributing open courseware.

• Most of these are available under some of a Creative Commons license, which makes them free to use and re-use.

Access to OCW Courses

• Most OCW courses are available in two forms:– Directly viewable in some kind of on-line

repository.– Downloadable in some form of package

The focus of this presentation is on expanding and improving support for OCW packaging creating an

installer application based on IMS Common Cartridges.

OCW Packages

• Early OCW packages where either simple archives (zip, tar, etc.) or an IMS Content Package (with internal manifest).

• The introduction of the IMS Common Cartridge specification provides a new packaging profile that should promote better interoperability for OCW.

IMS Common Cartridge

IMS Common Cartridges

• Web content, media files, and application specific files (Word, etc.)

• Assessments based on IMS-QTI 2.1

• Discussion forum topics

• Metadata using Dublin Core

• Remote authorization to protect intellectual property

Common Cartridge Package

Object folder

Object Resources

Associated Content

imsmanifest.xml

Web Content Metadata

Question Bank

Resources Supported

• Additional web content• Links• Discussion topics• SCORM package• Assessments• Question bank references• Inter-package references

Additional Info

• Each package can contain metadata, either embedded in the manifest, or in a separate file and a question bank in IMS-QTI 2.1 format.

• The IMS Common Cartridge specification has not been ratified by the IMS community at this time and is not publicly available. This is expected soon.

Open Knowledge Initiative

OKI v3 OSID Initiative

OKI v3 OSIDs,C’est Arrivé!

Problems Addressed

The V3 OSIDs, though still preliminary, address problems of:

• Session based threading, • Transactions• Unified handling of metadata • Abstract definitions vs. specific bindings• Problems identified in the v2 OSIDs

Filing OSID

FilingManager

FilingProfile DirectoryAdminSession

DirectoryEntryLookupSession

DirectoryNotificationSession

DirectorySearchSession

FileNotificationSession

FileSearchSession

FileSession

This session oriented approach is one of the new design

patterns that shows up through out the v3 OSIDs.

Design Challenges

– Most OSIDs are an intermediate service layer between an application and system services.

– In this case, it is a layer between the installer application and Sakai services (CHS).

– The Filing OSID is designed to be more generic than the Content Hosting Service at it exists in Sakai.

– Revealing detailed functionality through a generic interface can be challenging.

Data Streaming

Zip File I/O

OutputStream FileSession

Input Output InputStream

CHS Storage

FilingManager CHS Service

Application Filing OSID CHS Service

This coupling is a design challenge

Separate Processes

Zip File I/O

OutputStream

Input

Output

InputStream

CHS Storage

Application Filing OSID CHS Service

Three Solutions

Three possible solutions were explored:• Spawn threads to handle each phase of the

data transfer process. • Write the entire data block to the front. • Short-cut the whole chain.

Each of these potential solutions have problems…

Problems with Spawning Threads

• Threads are closely managed in Sakai.• Closely associated with specific types of

activity.• While possible to spawn and use a generic

thread, it is complicated.• Synchronization, blocking I/O, deadlocks, etc.

Problems with Writing All Data

• Writing the whole data block to the stream results in some very large buffers for large media files (such as video).

• Memory resources are limited.• Too easy to end up with multiple copies in

memory.

Problems with Using Shortcuts

• Creating a short cut involves an out of band agreement that reduces interoperability and subverts the OSID.

• OoBA take away from the interoperability that the OSIDs seek.

Solution Used

• Regardless of these problems, the current implementation loads all data into memory and uses a OoBA to communicate this data to the final content commit into the Sakai Content Hosting Service.

• Besides actually working, this is fairly efficient, reducing install time required.

The Installer Application

RSF PresentationLayer

Filing OSIDImplementation

Content HostingService

cc-installer

SakaiResources

IMS-CC

CC-Install User Interface

• Current implemented in RSF.• Three page views:

main upload results

Select Target Directory

File Upload

Results

More Work to Do

• Application is not 100% based on OSIDs yet – need to use DirectorySessionSearch

• Complete the Filing OSID implementation.• Re-implement back end onto a file system to

show portability.