Use of DVD-RAM Discs with CIRSI.

Craig D Mackay, Institute of Astronomy, University of Cambridge, England: 26/05/01.

The 2001 update of CIRSI has included the installation of Panasonic DVD-RAM drives on both the camera control computer (CIRCC) and on the remote control computer (CIRDR). The intention is that these drives can be used for rapid backup of the data taken by CIRSI at the telescope without having to go through a lengthy process of transferring the data onto another machine and then writing a DAT tapes.

1. General Description

The DVD-RAM drives used rewritable media with capacities of 4.7 gigabytes (single sided) and 9.4 gigabytes (double sided). The double sided drives are simply reversible single sided ones. In order to use the second side of these units be DVD-RAM has to be removed from the drive and reinserted upside down. These DVD-RAM media are fully rewritable, and therefore it is possible to erase and rewrite as required. The use of DVD-RAM media does not in any way preclude the use of tapes (or anything else you want to use such as a paper tape or punched cards). DVD-RAM drives are also available back in Cambridge. One of these is installed in the duplicate CIRSI control computer in CDM's Lab in the SPO. A second unit is available installed in an external unit so that it may be moved around and attached to any computer that has the appropriate DVD-RAM software package from Panasonic installed in it. Please note that at present there are no Linux drivers for this unit and therefore it is important to be able to mount the unit on the computer that can export the data to the UNIX systems.

2. Formatting the Media

Before you use any DVD-RAM media you must format it first. There is a programme available (Start/Programs/Panasonic DVD/DVD Form) which must be run in order to format the drives. Click on this if it is not available as an icon on the computer as desktop and this starts the DVD Form programme running. The media you have inserted into the drive should be recognised by the system. You need to select the format that you will use to format the media. You should always choose FAT-32 as the format of choice since this is optimised for large data volumes and is fully compatible with Windows 98, Windows 2000 etc. When you select this and try to format it will give you are warning message that this format is not compatible with older versions of Windows 95 and Windows NT. Confirm that you do indeed want to use this format. It takes approximately 40 seconds per side to do this formatting.

3. Transferring Data to the DVD

In order to copy data from the control computer the data drive to the DVD-RAM you simply have to open the two drives (called D:\ and E:\ (Removable Drive). Then transfer the data you wish to backup using the usual Windows techniques (select/copy/paste) onto the removable media. The data transfer rate is approximately 4.7 gigabytes transfer in one hour. Once you have created the DVD-RAM backup of your data you should remove it from the computer and check that you can read it on the other DVD-RAM drive which is in the control room computer. This is important just to make sure that you do have a backup that is indeed readable on a different machine from the one on which has written..

4. Other Ways of Backing Up.

You can also choose to backup the data by transferring it over Ethernet onto a Sun disk and then back your data up using a DAT tape as normal. In order to do this transfer you should remember that the local system at the INT/WHT no longer runs the Samba package which is used at Cambridge. This means you simply cannot mount the remote computer for direct bidirectional file transfer. Instead you have to use the Win-FTP package installed on the computers that allows file transfer between to computers.

Prepared by Please contact with comments, etc. Last updated 26 May 2001