Guralp Systems Limited


1. Introduction 2. Installing the CMG-DCM 3. Usage 4. Tools 5. Data transfer 6. Configuration 7. Configuring digitizers 8. Inside the DCM 9. Connector pinouts 10. Sensor and digitizer types 11. Revision history

Section Index: 4.1. Summary 4.2. Process Overview 4.3. Data Viewer 4.4. Data/Status Summary 4.5. Disk files 4.6. Flash files 4.7. Disk tools 4.8. Camera 4.9. Recent Log Entries

Chapter 4. Tools

The menu bar of the DCM's Web site is divided into four sections.

4.1 Summary

This link displays a page summarizing the current setup of the DCM. When you first log in to the module over its Web interface, this is the page you are initially presented with. It is divided into a several sections:

Serial ports

This table shows all the serial ports connected to the DCM, with information about each one. Each row also contains lnks to configuration pages for the port and any digitizer connected to it.

The table is also shown when you choose Configuration – Serial ports. For full details on the table and on serial port configuration options, see section 6.2, page 82.


This section displays the time the DCM last rebooted and calculates how long it has been running since that time.

Disk/Flash Status

This section reports the current status of the DCM's storage media.

A standard DCM has two Flash partitions mounted at /nand0 and /nand1. These are used alternately to record data. If the DCM has recently used its USB disk, this will also be shown in the table.

The DCM does not power up the USB interface specially to build this table, so if you remove the USB disk the DCM may continue to include it in the table until it attempts a disk operation.

Tamper lines

This section, if present, reports the status of the tamper lines relayed to the DCM over an external State of Health interface:

Input State Last Closed (Low) Last Open (High)

0 open (never) Wed Jul 7 16:04:48 2004

1 open (never) Wed Jul 7 16:04:48 2004

2 open (never) Wed Jul 7 16:04:48 2004

3 open (never) Wed Jul 7 16:04:48 2004

4 open (never) Wed Jul 7 16:04:48 2004

5 closed Wed Jul 7 16:04:48 2004 (never)

6 open (never) Wed Jul 7 16:04:48 2004

7 closed Wed Jul 7 16:04:48 2004 (never)

8 closed Wed Jul 7 16:04:48 2004 (never)

9 closed (never) (never)

10 closed (never) (never)

11 closed (never) (never)

12 closed (never) (never)

13 closed (never) (never)

14 closed (never) (never)

15 closed (never) (never)

The columns in the table give, in turn, the current state of each switch and when it was last observed to be in each state. The above example shows a typical reading for a set of 9 tamper switches that have not triggered: the normally-closed switches show the current time under “Last Closed”, and the normally-open switches under “Last Open”. All other fields show (never), indicating that no switches have been observed in the “wrong” state since the DCM was last booted.

Network configuration

This section displays basic information about the DCM's network setup. It is identical to the output from the Linux ifconfig program. A typical reading might look like this:

eth0 Link encap:Ethernet HWaddr 00:D0:1F:34:EB:08

inet addr: Bcast: Mask:


RX packets:3619 errors:0 dropped:0 overruns:0 frame:0

TX packets:2453 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:100

RX bytes:290005 (283.2 kb) TX bytes:417231 (407.4 kb)

Interrupt:42 Base address:0x8300

For further information, see the Linux manual page for ifconfig.

DNS configuration

This section reports the current status of the DCM's domain name resolution service. This is done by presenting the contents of the standard Linux /etc/resolv.conf file.

# eth0 begin

domain guralp.local



# eth0 end

For further information, see the Linux manual page for resolv.conf.

Unique IDs

This section contains unique identifiers for each of the hardware boards inside the DCM.

If you have a problem with the DCM, or it seems to be damaged, we may ask you to provide us with these IDs. You should write them down and keep them safe in case you cannot access the Web server in this event.

Software Versions

The final section lists the software currently installed on the DCM's Linux operating system, together with each program's version number. If you need to contact Güralp Systems about any of the installed programs, you should quote the version number in your correspondence.

4.2 Process Overview

Clicking Tools – Process Overview displays a page containing a list of all the processes currently running on the DCM. The list is generated using the standard command ps.

Some processes are required for the Linux operating system to function. You cannot change or restart these processes from the Process Overview page. Other processes are shown with a short description and control options.

If a Restart link is shown beside a process, clicking it will kill the process and run a new one. This is useful if a process appears to have stopped responding.

Restarting some processes may cause data transfer to be interrupted. For network services, clients will normally have to reconnect to the DCM to resume data transmission. In some cases, data may be lost. If you are unsure, contact Güralp Systems.

If a Configure link is shown beside a process, clicking it will take you to the DCM configuration options which relate to that process. For some processes, more than one link is present. For example:

4.3 Data Viewer

The Data viewer page uses a simple Java applet to enable you to check that the DCM is receiving data correctly. Your browser must have Java installed for you to be able to do this.

The data viewer is not intended to be a fully functional data visualisation tool. Scream! and similar software packages offer a full range of facilities for displaying and manipulating seismic data, either as it arrives or from stored data files.

The main part of the display shows a selection of the data streams being recorded, whilst the bars at the top and bottom allow you to control what is displayed, and in what manner:

If you cannot see any data in the Data Viewer, you should check first that

The icon bar

The bar at the top of the applet allows you to alter how the data is displayed. If you are familiar with Güralp Systems' Scream! package, you will recognise the icons in use here. There are:

The stream list

Below the display is a list of all the streams currently being recorded by the DCM. Each has a checkbox indicating whether that stream is currently being displayed.

To the right of the checkboxes, you are given information about each stream, similar to that found in the main window of Scream!. The information provided is:

4.4 Data/Status Summary

This link displays information about the data streams being received by the DCM.

This page is updated every 10 minutes. If you make a change to your installation, you will need to wait 10 minutes before it will be reflected in this page.

At the top of the page is a Stream Summary table. This table lists all the data streams which the DCM has received in the last 10 minutes.

Below the stream table, the DCM prints out the content of the latest block produced by each status stream. You can use this to check on the health of your digitizer.

Finally, at the bottom of the page, is a table headed Shared Memory Diagnostics. This table lists the number of blocks which have passed through the DCM's internal shared memory areas. One shared memory space is allocated to each input port, but extra areas may also exist.

The entries in this table give the key index of each shared memory area, its name (if it has one – this may be taken from its allocated port), and the number of data, status and CD blocks received.

The “Bad blocks” column reports how many corrupt blocks have been detected in this shared memory area. A “bad block” is either one which could not be parsed, or one whose checksums do not match the data. Bad blocks are noted, but not discarded.

4.5 Disk files

This link allows you to browse through any files currently on the DCM's primary hard disk.

The name of each file is shown, together with its size. If there are directories on the disk, they are shown at the end of the list. The amount of free space on the disk is also displayed.

Click on a link to download a file or enter a directory.

If no suitable storage medium can be found, the module will report the error Failed to open USB disk.

4.6 Flash files

This link opens a page similar to Disk files, but which explores the DCM's internal Flash memory.

The two directories nand0 and nand1 denote the two regions of Flash memory used by the DCM to store data. Click on one of them to view the files.

4.7 Disk tools

The buttons on the Disk tools page allow you to perform some important actions on the DCM's primary hard disk.

By default, the module looks for a connected USB hard disk to use as its primary storage medium. If no suitable storage medium can be found, you will see the message Failed to find a USB disk when you attempt to perform any of these actions.

Partition and format disk

Before using the CMG-DCM you should ensure that its primary hard disk is ready to receive data by partitioning and formatting it. The DCM uses a special journalling format for the hard disk which is designed to maintain the integrity of your data at all times.

The hard disk is guaranteed to contain a FAT32-compatible filesystem, even if a write operation fails or is aborted suddenly.

To format the disk, click Partition and format disk. You will be taken to a confirmation page.

Check disk filesystem

Clicking on this button will verify the integrity of the hard disk's filesystem. It is recommended that you do this immediately after installing the device.

Flush flash

Clicking on this button will cause the DCM to dump the current contents of its Flash memory to the hard disk, thus synchronizing it with the most current data. If you want to remove or replace the DCM's hard disk, using this tool will ensure that the outgoing disk is up-to-date.

Flush flash does not remove data from the DCM's on-board Flash memory. If you Flush flash and then swap hard disks, the data remaining in memory will later be written out to the new hard disk, causing some overlap between it and the old disk.

Whilst the DCM is copying the contents of the Flash memory to disk, you will be shown a log of its progress. The USB interface allows data transfer at a speed of around 100 Kb/s, so large files may take several minutes to complete. If an error occurs at any point, it will be marked in red.

4.8 Camera

If you have attached a compatible camera to the external USB port of the DCM, clicking on this link will show the current view from the installation site. A new image is retrieved every 12 seconds, or whenever you reload the page. Güralp Systems can supply a compatible camera with the DCM, although any STV0680-based device can be used.

4.9 Recent Log Entries

This link displays the most recent 300 entries written to the DCM's internal log file.

Each entry includes, in order:


1. Introduction 2. Installing the CMG-DCM 3. Usage 4. Tools 5. Data transfer 6. Configuration 7. Configuring digitizers 8. Inside the DCM 9. Connector pinouts 10. Sensor and digitizer types 11. Revision history