Years before I started working on Intel AMT, designers where creating a list of usages that would be enabled by Intel AMT. The list included, I presume, usages around 3PDS, remote reboot to BIOS, disk redirection, etc. Many of the Intel AMT usages that are promoted on the Intel web site. When I started work on the DTK, a personal challenge had always been to find new ways of using existing features to do different and sometimes unexpected things. Create new usages for Intel AMT that it was never originally designed to do. I now present my top 5 abuses of existing features.
TCP-over-Serial-over-LAN. The Intel AMT serial port I am told, was originally designed as an easy way to remotely take control of the BIOS and recovery OS remotely. Designers needed a way for BIOS to be able to send test display data to a remote console. A virtual serial port was a great solution. It so happens that in the original design, this serial port was always enabled and usable, even when the normal OS was running. This allows a serial agent to talk to a console while bypassing the OS’s network stack. This is interesting on its own and I started work on a serial agent of my own. Things took a weird twist when I started sending binary data and sending files over this serial port, making it very valuable. It’s only a few weeks later that I realized I could also send TCP traffic over this serial link, making it possible to contact TCP services on the Intel AMT computer even if the network stack was disabled. A few days later, I showcased the first demonstration of VNC-over-SOL, and turning this abuse of the serial port into an instant hit. To this day, VNC-over-SOL is still, one of the most impressive demonstrations of Intel AMT.
Reverse Watchdog. When Intel sales people demonstrate Intel AMT to customers, they often get asked if you can shutdown gracefully an Intel AMT computer using Intel AMT. The simple answer was no, Intel AMT will perform a brutal shutdown or reset upon request. To perform operations like a clean shutdown or reset, sleep or hibernation requires the involvement of the OS. You could tell a serial agent like Intel AMT Outpost to perform the shutdown, but that required opening the serial connection and could be a problem if you had to shutdown many computers. I needed a way to pass a small amount of information to a running Intel AMT agent on the PC, do it using SOAP/WSMAN only and if possible get confirmation of reception. We could store the command into 3PDS and have the agent read it periodically, but 3PDS required setup and that little amount of data would have required allocation of a 4K flash page. The solution came when looking at the agent presence feature. When a console creates a new agent, the agent can now register this agent locally. The agent also get the timeout of the agent in seconds (from 1 to 65535), this would be the key. By constantly trying to register a known GUID, Intel AMT Outpost could see if the agent existed or not. If suddenly the registration works, the timeout value would indicate that type of shutdown operation to perform. Better yet, the simple fact that registration occurred changes the state of the agent to “Running”, confirming to the console that the message was indeed received. Today the Intel AMT Terminal has “Agent Commands” in the remote control that allows a user to perform soft operations when the agent is running, even if the OS network stack is not working.
Mouse over serial. A few months back I started work on a smaller version of Intel AMT Outpost called Intel AMT Guardpost. The idea was that if a serial agent was going to be useful, it was going to need to run on a recovery OS, run in the background with no dependencies and with as little footprint as possible (Is it not annoying to have all there background processes running?). The C/C++ version of Intel AMT Outpost was on its way. One feature I always wanted to work on was a remote Windows command prompt; it took over a week to finally pull this off. I could now remotely shell to DOS and perform basic command line operations. I could also enter the command like editor with the “Edit” command at which point, the temptation to support the mouse-over-serial-over-LAN was a must have. Using the binary serial protocol, I added the support to the terminal in a few hours. To this day, it’s still a fun and amazing demonstration of outstanding remote manageability.
IDE-R within the OS. A few days after first enabling IDE-R within Intel AMT Commander, I stumbled upon something I had not noticed before. If an administrator where to start IDE redirection and the OS was to re-scan its plug & play devices, the additional floppy and CDROM drive would show up in Microsoft Windows. This was immediately interesting since transferring files over the serial port was limited to 115kb/sec a very slow speed in today’s world. With IDE-R, you can copy files at around CDROM 4x speed on a local network. All I needed was a way for Intel AMT Outpost to cause the OS to rescan its plug & play devices. A few hours later the “HWRESCAN” command was built and for the first time, an administrator could mount a CDROM remotely and install a patch as high speed without ever using the OS’s network stack. This feature also turned out to be an excellent compliment to VNC-over-SOL.
Fast data path using IDE-R. This is not an idea I never built into the
DTK, but I wanted to add it to this list since it would also be an interesting was to use existing features in new ways. The serial-over-LAN feature turned out to be extremely valuable, but it is also slow. Serial ports are very inefficient. One way someone could speed things up is to use IDE-R as a fast by-pass to the OS. An administrator would mount a virtual floppy disk drive containing a single file. This file, would not really exist, it would contain different data each time it was read, making it possible to send data to an OS agent thru Intel AMT at much higher speeds. Also, since the floppy is a read/write device, the agent could write into the virtual file data that it wants to send to the console. It would be quite a bit of work to pull this off, but it certainly seems possible. Someone would just have to know the internal format of an .img file.
That’s my top 5. I realize this is probably a rather advanced blog article, but this is proof that you can have a lot of fun to any technologies.
Ylian (
Intel AMT Blog)
