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Last month I posted about Ian Pratt's presentation on the Xen Open Source Hypervisor at the FOSDEM (Free and Open Source Developer's European Meeting) Conference. FOSDEM has posted videos of all the sessions. As the one of the primary founders of the Xen Open Source Hypervisor Project, Ian has unique insight into the Xen Project. http://video.fosdem.org/2008/maintracks/FOSDEM2008-xen.ogg
Simon Crosby 
, the CTO of the Citrix Virtualization and Management Division, was interviewed recently at VMWorld Europe by Tarry Singh of Virtualization for Everyone .
Here is how Tarry describes the interview on his blog -
Talking to Simon is always a pleasure. A gentleman with deep understanding of the dynamics of the enterprise. With XenServer, XenDesktop (soon to be GA) and XenApp, Citrix has a rock solid foundation within your data center.
Tarry has many more VMWorld Europe interviews on his blog of Virtualization for Everyone and at Virtualization.com .
Recently I published a video blog post about RAVE (Remote Audio & Video Extensions), the technology behind SpeedScreen Multimedia Acceleration. RAVE supports high quality playback of media streams that can be decoded by a media player that uses DirectShow or DirectX Media Objects (DMO). A question came in from the field asking how a customer can determine whether SpeedScreen Multimedia Acceleration is functioning. So here are some handy tips for verifying whether RAVE is working or not. In addition, you'll find a helpful troubleshooting article in our Knowledge Center.
The quick answer is that you can probably tell by the quality of the video playback since RAVE delivers a user experience on par with running the media player locally. But here are some other telltales. When RAVE is working, a black rectangle will quickly flash by as the video begins to play. Server CPU usage will be much lower than if the video were being rendered on the server (for comparison, you can disable SpeedScreen Multimedia Acceleration on the console and try playing the same video). Searching for "FilterInt" in ProcessExplorer will show that DLL loaded by the media player's process.
Are there any enhancements that you would like to see to make it easier to discover that an additional codec needs to be installed on the client (or even on the server to support server-side rendering as a fallback)? For example, one possible enhancement would be for SpeedScreen Multimedia Acceleration to record RAVE events in the Windows Event Log.
Derek Thorslund
Product Strategist, Multimedia Virtualization
Back in December I posted a video I found on YouTube called XenDesktop Caveman. I found a sequel recently on YouTube. Watch it below...
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If you missed the post by Bryon Thomas on the XenDesktop at Demo08, I found a version on YouTube (posted by InfoWorld).
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You can find out much more info about XenDesktop and the Tech Preview and participate in the community forums at the Desktop Virtualization section of Citrix Tech Talk.
In recent years, we've seen widespread adoption of video streaming in the enterprise. Typical uses include employee training and corporate communications. In this 10-minute video, Citrix engineer Aureliano Lopez-Martin demonstrates SpeedScreen Multimedia Acceleration and explains how Citrix's RAVE (Remote Audio & Video Extensions) technology delivers video streaming with excellent quality -- including High Definition -- and very high server scalability.
To set the stage, consider the two basic alternative approaches to delivering streaming media from a centralized application or desktop delivery system. You can either render the video centrally and send it in a standardized compressed format to the client, or you can decode the native compressed media stream on the client device using the appropriate codec. Each approach has advantages and disadvantages.
Recently, I posted a video of Vista Aero Remoting, a technology currently being developed under project Apollo. The Apollo Vista Aero Remoting technology takes a generic approach to delivering whatever appears on the user's virtual desktop. The beauty of that approach is that it delivers a "full fidelity" user experience for whatever the user needs to view on the screen, whether it is a Flash or Windows Media video, a next-generation Windows application written in WPF or Silverlight, or any other application technology.
The RAVE technology behind SpeedScreen Multimedia Acceleration is an optimization specifically for streaming video and audio. It leverages client-side resources to increase server scalability (the number of concurrent users) and thereby reduce the cost per user. Take a look at this video and you'll learn about the advantages and requirements of the RAVE approach and get a glimpse into the future of this innovative technology.
Derek Thorslund
Product Strategist, Multimedia Virtualization
(Click to hear Aureliano Lopez-Martin explain the RAVE technology behind SpeedScreen Multimedia Acceleration)
I'm back from my 7-day Eastern Caribbean cruise and of course the first thing on my mind is my Multimedia Virtualization blog! We've just migrated the Citrix blog site to an updated system so I had a few transitional issues to work through, but now I'm ready to share with you Part 2 of my series on optimizing Adobe Flash performance on Citrix Presentation Server. (Click here to read Part 1.)
There's definitely more to optimizing Adobe Flash than configuring SpeedScreen Flash Acceleration ("SpeedFlash") and making sure you have any required hotfixes to handle newer versions of Flash. One of the features of Presentation Server that can have a very substantial positive impact on Flash performance (animations and video) is Queuing & Tossing. This feature shows up in the management console as "Discard queued images which are replaced by other images" or "Discard redundant graphics operations", depending on which version of Presentation Server you're running.
The Queuing & Tossing feature of Thinwire briefly queues GDI draw commands and, before sending them over ICA, inspects the stack in reverse order (LIFO) to allow tossing of obsolete commands (those which have been overwritten by subsequent commands). The queuing period is short enough (30ms) that it doesn't degrade the responsiveness of the application; in fact, performance is significantly improved because draw commands that are logically redundant are discarded.
The tossing algorithm was enhanced in Presentation Server 4.5 (Ohio) to look for more graphics constructs. The tossing algorithm now uses a 1-bit-per-pixel map of the session screen. And it can detect complete self-contained 'frames'. As a result, Thinwire will either send the entire frame to the client as a self-contained entity or toss it completely. These improvements to the tossing algorithm further reduce the amount of data that needs to be sent over the wire. Along with reduced network bandwidth consumption, network efficiency (data bytes per frame) is increased. And the user experience is better because the entire frame gets updated at once rather than in pieces.
So, just how big a difference does all of this make? I recently spoke with one of our engineers who has been taking performance measurements with Flash videos. In his testing, he found that enabling Queuing & Tossing reduced bandwidth consumption by more than 3 times!
In addition to the new framing behavior of Queuing & Tossing in PS 4.5, just-in-time output behavior has further improved Flash performance. Flash video playback with PS 4.5 is noticeably smoother. And CPU consumption is lower, which increases server scalability (number of simultaneous Flash users per server).
There's still quite a bit more to tell you about Adobe Flash performance optimization, so stay tuned for my next installment on this topic.
Derek Thorslund
Product Strategist, Multimedia Virtualization
The new Xen Desktop will have an edition that includes three components - The Broker, XenServer, and Citrix Provisioning Server. Citrix Provisioning Server (formerly known as Ardence OS Streaming) often confuses people when they first hear about it. OS Streaming can be a difficult concept to grasp for many people at first. Once you do finally see the light, your jaw tends to drop as your eyes open wide. This video on YouTube is definitely a jaw dropper -
I heard this from a friend that this video was a huge hit at Microsoft Tech Ed in Orlando a few months ago. Justin Zarb blogged about it on Technet.com .
Its a pretty great demo, having the ability to stream individual operating systems over a 100mb LAN. The Citrix Stand at Tech Ed has been very entertaining and had some good information about the product set.
This video has been around for a while, so many of you may have already seen it. You may not have seen this next video. This video demonstrates the high availability option for Citrix Provisioning Server.
Citrix Provisioning Server is a key component of the upcoming Citrix XenDesktop release. There will be an edition of XenDesktop that includes both Provisioning Server and the XenServer hypervisor to provide a complete solution for desktop virtulization.
If you missed iForum 2007, there was a great demo of Provisioning Server at the keynote. You can watch the demo with Mark Templeton and Pete Downing here .
In this video, Pete Downing first takes two CPS 4.0 Servers and instantly upgrades them to CPS 4.5 (while removing the local hard drives). Next, Pete will drag and drop provision 9 CPS Servers, 11 IIS Servers, 5 SAP Servers and 5 Microsoft SQL Servers (all diskless) in a matter of minutes. For his finale, Pete then streams out the XenServer Enterprise hypervisor to all 30 servers and brings up all the OS images as virtual machines. Now that is OS Streaming Gone Wild!
BTW, if you missed the "Jellied Cat" video that Mark T. played during the keynote, here it is.
How long before we have jellied cat cars? <grin>
I am looking for more content specifically for Provisioning Server, so stay tuned.
UPDATE: Some additional third party content on Provisioning Server from the comments (Special Thanks to Wilco)-
Performance of CPS server based on Citrix Provisioning Server (http://sbc.vanbragt.net/mambo/white-papers/performance-of-cps-based-on-citrix-provisioning-server.html)
Explanation how tow run a CPS with Ardence OS Streaming
Beside I also have a review of the product it self:
http://sbc.vanbragt.net/mambo/deployment/ardence-os-streaming-4.html
Also take a look at http://www.virtuall.nl/videos/Ardence/ where Ruben Spruijt published some nice demo video's of the product.
One more link I have come across - http://www.Ardenceguru.com
Update2: One more link. Here is a presentation on the old Ardenc site that covers how Provisioning Server works with Citrix Presentation Server.
I am not sure who made this video that I found on YouTube about XenDesktop, but it is pretty funny.
I will post more about XenDesktop in addition to XenServer on my blog.
In my conversations with customers at our iForum App Delivery Expo in Las Vegas a few weeks ago, the topic of Adobe Flash came up several times. It became apparent to me that many Citrix system administrators are looking for guidance on how best to configure Presentation Server to support access to web sites with Flash content, and they're wondering what future enhancements Citrix has on our technology roadmap. So here is the first in a series of blog posts about optimizing Flash performance.
Flash is indeed a key focus area for the Citrix Multimedia Virtualization Initiative. Over the past few years we introduced various enhancements and tweaks to Presentation Server to help customers optimize the user experience when viewing Flash animations and videos. We also offer NetScaler to dramatically accelerate the delivery of web applications, including apps with Flash content. And there's more to come...
The reason for this continued attention to Flash is the growing prevalence of Flash-based content. Based on input I received from two leading Content Delivery Network vendors, it looks like Adobe Flash has now captured at least 10% of the enterprise market and is enjoying rapid growth. And a Forrester survey ("Enterprise Browser and Desktop Trends") of over 2,000 large enterprises found the Adobe Flash player installed on 98% of desktops.
The obvious starting point in our discussion of Flash performance is the SpeedScreen Flash Acceleration feature ("SpeedFlash" for short) introduced in Presentation Server 3.0. You can enable SpeedFlash to be on at all times or just over low bandwidth connections (less than 150Kbps). SpeedFlash automatically adjusts the Flash player to use simpler graphics (for example, no smoothing or anti-aliasing). These simpler graphics can be more effectively compressed, thereby reducing bandwidth consumption. CPU usage is reduced, too, which translates into higher scalability (more concurrent users per server).
SpeedFlash looks for specific binary file names. Here's where things can go wrong. The SpeedFlash code in Presentation Server 4.0 looks for flash.ocx and won't do its trick unless it finds that file. You may be running a version of the Flash player with a different binary file name. Presentation Server 4.5 was updated to also accept flash8.ocx, flash8b.ocx or flash9.ocx. But what do you do if you're still running Presentation Server 4.0?
There's a hotfix for PS 4.0 [NOTE: this hotfix is for Windows Server 2003] that adds support for Adobe Flash versions 7a, 8, 8b, 9, 9c, and 9d. You'll find the details at http://support.citrix.com/article/CTX115426 (login required). [NOTE: If you have trouble with this link even after logging in, just do a search for CTX115426. I've noticed that the link can take a long time to resolve. An approved support contract is required to access limited release hotfixes and hotfix articles.] The hotfix number is PSE400R03W2K3091. And I expect there will be future hotfixes as new versions of Flash are introduced that have a different binary file name or require new SpeedFlash code to achieve the task of adjusting the Flash player to use simpler graphics.
[UPDATE: A hotfix for PS 4.0 with HRP04 on Windows Server 2000 was made available on March 10th. Customers with an approved support contract can find the article describing this hotfix at CTX115555. The hotfix number is PSE400R04W2K012. This hotfix adds support for Adobe Flash versions 7a, 8, 8b, 9, 9c, and 9d.]
So, does it work? Obviously the current SpeedScreen Flash Acceleration technology is not as advanced as SpeedScreen Multimedia Acceleration, which leverages client-side resources to greatly improve server scalability and provide a just-like-local user experience for a long list of media types that can be decoded with a DirectShow codec. Yet the measurements I've seen for SpeedFlash show an impressive 22% average reduction in bandwidth consumption (the actual figure will vary according to the content).
If your users will be accessing Flash videos, I recommend setting SpeedFlash to be always on, rather than limiting it to just low bandwidth (dial-up) connections.
Audio settings are also important to consider since if you're watching a Flash video it more than likely has an audio track, too. I recommend Presentation Server's Medium Quality setting as the best compromise between sound quality and bandwidth consumption. The Low Quality setting does not make for a very good user experience, and the High Quality setting uses up a lot of bandwidth (roughly 1 Mbps). Improvements to audio support are another part of the Citrix Multimedia Virtualization Initiative (see "Now playing - The Ulysses Audio Codec").
I'll have some more "secrets" for optimizing Flash performance in a subsequent blog post.
Derek Thorslund
Product Strategist, Multimedia Virtualization
It's great to see the major desktop appliance (thin client) vendors, including HP/Neoware and Wyse, rallying around the Citrix Multimedia Virtualization Initiative. A notable example of how our ecosystem partners add value is TCX Multimedia 2.0 from Wyse, a streaming media solution (think training videos and corporate broadcasts accessed in an ICA session). At iForum 07 - The App Delivery Expo - Wyse and Citrix announced that TCX Multimedia 2.0 has achieved Citrix Ready status (see the press release from Wyse).
TCX Multimedia provides an intriguing complement to SpeedScreen Multimedia Acceleration (one of several technologies explained in Brian Madden's video on SpeedScreen). As with SpeedScreen Multimedia Acceleration, the media player runs on Presentation Server but the multimedia (video and audio) data stream is decoded and played locally on the client with a virtual channel being used for start/pause/stop and other controls. And both technologies deliver a great user experience by leveraging the processing power of the client device while maintaining the advantages of a centralized application delivery model. The key difference with TCX Multimedia is that the multimedia stream can be delivered directly to the user desktop appliance from a local media server instead of going through the data center. TCX Multimedia attempts to establish a direct path from the source to the client. This isn't always possible and the solution will fall back to obtaining the media stream through ICA when necessary to traverse firewalls, but when it is possible it has the benefit of consuming less network bandwidth and reducing the load on Presentation Server, which is good for performance and scalability (number of concurrent users per server). The beauty of the TCX Multimedia software is that it can intelligently and dynamically decide when to redirect the multimedia stream.
Another noteworthy feature of TCX Multimedia is its multicast support (limited to MPEG-1). Multicast provides a very efficient way of delivering the same multimedia stream to many users at the same time. Suppose your CEO is addressing the troops for a quarterly state-of-the-business update. Potentially a large number of people want to watch the videocast simultaneously, in real time. With multicasting, each individual packet can be sent to many endpoints simultaneously, consuming much less network bandwidth than if the media stream had to be replicated for every user. And multicast uses UDP/RTP. UDP (User Datagram Protocol) is better suited to live videocasts than TCP/IP because it is a "best efforts" protocol that doesn't get stuck doing retransmissions if some packets are lost; timeliness is more important than completeness. RTP (Real-Time Protocol) adds timestamps and other controls to help keep the audio and video in sync.
TCX Multimedia supports a broad set of media formats: MPEG-1, MPEG-2, MPEG-4 part 2, WMV (Windows Media Video), WMA (Windows Media Audio), AC-3 (Dolby Digital) and MP3. The notable omission at this time is Adobe Flash.
What next? Wyse notes that support for Linux is "coming soon".
Derek Thorslund
Product Strategist, Multimedia Virtualization
The Citrix Multimedia Virtualization Initiative is an ongoing cross-product R&D effort focused on multimedia desktop and application delivery. Watch my video blog for a 6-minute introduction to the Multimedia Virtualization Initiative and learn how Citrix is continuing to enhance the ICA protocol to provide the best end-user experience as graphics and rich media technologies evolve.
My video blog references Microsoft Windows Presentation Foundation (WPF) technology and a fast-paced video that will give you a great appreciation for what WPF applications are all about. You can find Microsoft's WPF video at http://wpf.netfx3.com/blogs/news_and_announcements/archive/2007/05/10/wpf-momentum-video.aspx.
Derek Thorslund
Product Strategist, Multimedia Virtualization