La Silla Observatory



DRL replacement to the w*off machines
User's Requirements


SciOp Internal Use Only
Prepared Olivier Hainaut
Reviewed Gaspare LoCurto
Released Olivier Hainaut 2002-12-15

Revision History

2003-03-29 first draft, ohainaut
2003-04-14 includes comments from SciOp - G.LoCurto




Currently, the w*off (wg5off, w3p6off, w2p2off) machines are HP workstations that receive the raw data from the w*dhs machine. They are meant for the observer to work on his data. They feature a set of data processing tools and recipes. They are also used to store Service Observing data before their distribution, and to store technical data being processed by the various instrument scientists.


In this document, "he" and "his" refer to the position described. In practice, these position can be occupied by people of any known or unknown gender. So, this note replaces all the she/her.


SciOp: La Silla Science Operation Department
LED: La Silla Engineering Department
MET: MEdium-sized Telescope Team (current) or Section (in Sciop)
OpA: Operation Astronomer
TIO: Telescope and Instrument Operator
SEST: Sweeden/ESO Submilimetric Telescope
APEX: Atacama Pathfinder EXperiment
IFo: Instrument Force
IFoL: Instrument Force Leader
AS: Astronomy Section
ASL: Astronomy Section Leader


2.- Requirements

2.1- Hardware

COMMENT (RME): WFI we should have a system that can expand to a multi-processor (4) CPU. These are available on the market.
REPLY: agreed on multiprocessor capability, but do we really need 4 ?  Before installing more processors should be cheked whether the software (IRAF, MIDAS etc.) is able to run in parallel in more than 1 CPU. Thext modified

CPU: state of the art, typically a Pentium-4, around 2GHz clock. Capabilities for expansion to multiprocessor would be a plus, although it is not clear at this point if we would benefit from this.

COMMENT (RME, EPO) While for other instruments 512MB is fine WFI needs 1GB fast RAM.
REPLY: agreed

MEMORY: minimum 512Mb, ideally 1Gb fast RAM. 1Gb fast ram required for w2p2drl (WFI's).

COMMENT (JPR, EPO): we should consider a RAID array for WFI to reach the planned 720Gb (ask suggestions to NGAST ?) 
REPLY: agreed, although this is a technical specification, not a requirement: text changed:

For 2p2, the equivallent figure (6n * 30Gb * 4 = 720Gb) might be beyond what is available on the marked. A possible solution would be to install that disk as a RAID totalling 720Gb.

COMMENT (GLO): HARPS will record (on the basis of the commissioning 1 statistics) from 5Gb to 10Gb per night. A 240Gb disk volume is therefore requested.
REPLY: text changed:

 The operating system should be configured in such way that it recognises and mount automatically these disks, and permits the users to umount/remove them without root privileges in a documented way.

    We should have at least 2 USB2/Fireware slots per machine    to avoid conflicts between users/visitors.
Reply: made more clear:

...the machine should have at least 2 USB2/Firewire slots

COMMENT (JPR):     I would strongly support dual head systems. I note that the
        Dell Precision 650 with nVidia, Quadro4 900XGL, 128MB,         VGA/DVI comes dual monitor capable.
REPLY: dual display would be a nice feature, but is not critical.     However it would be wise to choose dual monitor capabale     platforms like the ones John is suggesting or MacIntosh     (with linux & Scisoft).

COMMENT (JPR): As there are several standards for DVDs (DVD-R, DVD-RW, DVD+RW...) it is important to check which standard the drive will support. These days it is possible to get drives compatible with more than one standard (though not necessarily from Dell), e.g. the Sony DRU-500A Dual RW DVDRW, see for example
REPLY: agreed. Text added:

COMMENT (RME):    DLT writer for w2p2off is required.

REPLY:        will this requirement stand also after we will have a central backup office in La Silla ?

COMMENT (GHA): There should be a read-only CD/DVD reader and an CD/DVD burner (I would opt for the DVD burner since there will be no need for any upgrade, and astronomers can burn their data in one go if they have multiple nights.  Same for the TiOs so means less work). The reason why there should be a separate read-only CD/DVD reader is to avoid having to dismount the CD when using xcdroast. If we have only one CD/DVD writer It is easy to have conflicts if the kernal tries to mount the CD, whereas xcdroast want to write to the CD.
REPLY: I beleieve we could find a better solution than buy read-only CD/DVD to avoid conflicts in the system when using xcdroaast.  A possibility would be to start xcdroast from a script which checks that all mounting is done correctly. Pls note that the TIOs will have nothing to do on this machine: this will be for the visitors and SciOp astronomers to play with their data, not for data archiving and CD production (which is done eleswhere)Text added:

There should be a scratch area for the CD images, or that xcdroast is configured to use /tmp or /data (this requires root permission).
REPLY: agreed.
Added in the configuration of XCdRoast

COMMENT (GHA): About the CD/DVD burner/players -- if the computer will be physically in the computer room, we should consider using external (fireware or USB) CD/DVD burner/players which are accessable from the desk, and does not involve the user going to the computer area. This also may be configured as part of the auto-detection of external hard disk setup.
REPLY: desk accessibility to CD/DVD burner is desirable but not critical. We should investigate possible solutions.

CD/DVD: a read-only unit, and a read-write unit. External unit (USB2/Firewire) living on the desk as opposed to the computer room would be a nice luxury provided that this does not degrade transfer rates.

COMMENT (GHA): I would advice against using the "ergonic keyboards". Also, the keyboards must be US standard.
REPLY: agreed.

2.2 Software



In addition to the various system related accounts:

COMMENTS (GHA): >> The paths should include a /home/user/bin as default so that additonal programs can be installed by us.  There should be a scratch area for the CD images, or that xcdroast is configured to use /tmp or /data (this requires root permission).  It should also be decided whether KDE or GNOME should be run. At the moment the different drl machines are configured differently.
REPLY: agree, but users should avoid to install unsupported software or they should ask the requested softwarto be entered in the supported software list.

Additionally, the accounts should be configured to use GNOME, and the path should include a ~sciops/bin directory so that we can install programs under configuration control but without inserting them in the standard configuration.