Minimum Requirements and current NRAMM setup¶

Electron Microscope with its Controling Computer (Windows)¶

Microscope need to have the capacity for external control and network connected (See Network Configuration section for details on that. Here are known examples of Leginon implementation:

• FEI: Tecnai, Polara, Titan Krios with TEM Scripting
• JEOL: 1230, 1400, JEM3100FSC, 3200

Digital Camera¶

Gatan, Tietz, FEI Eagle-minimal 1kx1k, Direct Electron DE-12

Note: We are working on FEI Falcon camera integration.

A Second Computer Running Linux (CentOS at NRAMM)¶

At NRAMM, we separate the three activities into different computers that serve about 15 people with three microscopes that could be running at the same time. All scopes share the same database, web server, and file server. Each microscope has its own processing computer.

We don't recommend using a computer with Windows PC as the second computer as an option.
One group is able to use an unusually power WIndows PC (The one come with Gatan K2 Summit) as the processing server. However, it is suspected as the reason for the acquisition of frame saving super-resolution mode to fail.

CPU¶

Minimal 2 GHz;

NRAMM:

• Processing server: Single quad core (Intel Xeon E5540 2 2.53GHz). One computer per microscope.
• Database server: Duo quad core (2.6GHz)
• Web server: Single quad core (Intel Xeon 3.00GHz)

RAM¶

The whole system with its image processing, database query and web serving, needs a lot of memory. Realistically, you will need minimal of 4GB memory for all processing+database+web server activities for one microscope operation with 4k camera that serves two persons (one operates the scope, one just look at the images from the web viewers) at the same time. We know of at least one successful daily usage at this configuration. For 2k camera, an all-in-one computer with 3GB memory has also been used successfully. If you are buying a new computer, get at least 6GB memory would be a good idea.

At NRAMM, to serve about 15 people viewing images and with three microscopes that could be running at the same time:

• Processing server: 4GB physical memory and 2 GB swap for years, and now at 6GB and 6GB, respectively. One computer per microscope
• Database server: 16GB memory and 18GB swap.
• Web server: 4GB memory and 6GB swap.

File server¶

10 GB for the softwares and maybe a few hours worth of data collection. Much larger
for routine use. NRAMM 45Tb on raid and growing although some are archived.

Network connection speed¶

100 Mbps might be possible; NRAMM 1 Gbps

Additional need for frame-saving direct detection camera¶

File server¶

Frame-saving camera such as DE-12 and K2 Summit are capable of saving movies of an exposure in addition to returning an integrated image back to Leginon. As a result, if the function is used, the disk space required is multiple of that of the image. Leginon saves the frames as non-gain corrected 16-bit integer, rather than dark/gain-corrected 32-float mrc. Therefore, the additional storage requirement is approximately number_of_frames/2 times larger. Typical number_of_frames used in DE is 10-50 frames and in K2 Summit 20-30 frames. These frames should be off-loaded from the camera computer or saved to network drive as soon as possible so not to over-load the camera computer.

In addition, to use the information in the frame movies, these raw frames must be gain/dark corrected and saved as 32-bit float mrc stack. For K2 Summit Counted/Super-resolution mode, the alignment of the frame is also esssential. This means that at some point, the data related to one image will be

number_of_frames * (0.5 + 1 + 1)

times more than non-frame saving ones. Factoring in that hundreds of such image may be acquired within a 24 hr session, it is therefore important to take this into account in allocating the data storage system for long term.

NRAMM's current setup:

1. Raw frames are transferred off camera with rsync using rawtransfer.py which also removed the finished frame stack on the camera to make room for more to come.
2. These raw frames are needed if default frame processing does not give optimal results. We keep these on network drive for 30 days and make it user's responsibility to archive this on external drives.
3. In the frame processing Appion script, if frame alignment is performed (usually finished within a day or two after data acquisition), the un-aligned frame stack is removed since majority of the problem require re-correction.
4. The frame-aligned stack is integrated and saved in the Leginon database as "-a" images. 95% of the users do not require frame-aligned stack after this point.

DD Frame-alignment server¶

A good gpu is needed for frame alignment and if real-time speed is desired, parallel processing on multiple hosts may be needed.

minimum: A CUDA 5.0 capable standard linux computer that you don't need to access its monitor (and hence using gpu for display) during the alignment computation.

NRAMM's current best setup:

• up to 4 node gpu cluster each with 128 MB RAM and Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz & NvidiaTesla M2090 GPU. (These have 16 cpu but only one is used per job)

Leginon system components developed at Leginon home¶

Leginon Home: http://www.leginon.org/

Supporting packages and programs available through internet or your Linux distribution¶

There are minimum of ten packages or single programs, some of them are included in your
Linux distribution.

Leginon supporting programs available upon request¶

adaexp.exe that is required if film exposure is to be made through Leginon on FEI Tecnai
machines is available by request. Please contact Max Otten: (mto at nl.feico.com)
and let him know what version of the Tecnai user interface you are using.

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