Guralp Systems CMG-DCM build <10,000 - Manual (Page 140)

Acquisition Modules and Platinum Firmware Recording and Retrieving Data
11.2.1.1 Storage device
The “Storage device” tab has the following fields:
Storage device: This drop-down menu lets you choose from the storage
options available on your system. The options may include one or more of:
• “Removable USB disk in internal tray” - this is the default setting for
CMG_EAMs and CMG-DCMs. Data are written to the removable
USB/FireWire disk and can be read via the web interface, the command
line or by removing the mass storage device and attaching it to an
external USB or FireWire host, such as a PC or laptop.;
• “External USB drive on mil-spec connector” - data will be stored on
external media, which should be attached to the USB connector. The
Pt-storage daemon handles the required operations for mounting and
un-mounting the file-system;
• “Internal USB storage” - for cylindrical digitisers only, data can be stored
on internal USB-accessible flash memory. It can be retrieved by a USB
host (such as a laptop) connected via the GPIO connector. See section
15.1.3.1 on page 256 for more details;
• “Ring buffer on flash module” - some systems are equipped with an
external flash module to extend the storage capacity beyond that
available on the normal file-system. Data written here are accessible via
the web interface or, from the command line, under the path
/media/flash_module;
• “Record files under /var/spool/recdata” - this is the only option on
CMG-NAMs and CMG-NAM64s and it is not available on other
platforms. Data are written directly to the internal hard drive and are
accessible via the web interface or, from the command line, under the
path /var/spool/recdata.
• “Remote NFS mount” - this option causes data to be written to a remote,
network-accessible storage device that uses NFS as the underlying
protocol, such as NAS units. See section 11.2.1.5 on page 144 for
configuration details.
Recycle space: If this check-box is set to zero, gdi­record will write to the
storage device until it is full and then stop writing. The module will check
periodically for free space and start writing again when it can. This prioritises
the earliest data at the expense of the most recent data.
If the “recycle space” field is set to any other numerical value, it is interpreted
as the amount of free space, in MebiBytes, to leave on the disk. When this
value is approached, older data are deleted to make space for the current data.
This prioritises the most recent data at the expense of the earliest data.
MAN-EAM-0003 140 Issue E - February 2014