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Mark5B disk data format
Taken from Mark5B System User's Manual (9 June 2006) Section 5.
Data on disk is divided into equal-length disk frames (DF). Each DF has a header of 4 32-bit words followed by 2500 32-bit words of data (10000 bytes). The DF boundary is aligned with the UT second tick.
Disk Frame Header
| Word 0 | Synchronization word (0xABADDEED) |
| Word 1 | Bits 31-16: User specifed |
| Bit 15: T - tvg data (test data if set) | |
| Bits 14-0: DF # within second | |
| Word 2-3 | VLBA BCD Time code and 16 bit CRC |
| Sync word (32 bit) | ||
| User-specifed (16 bits) | T | Frame# within second (starting at 0) |
| VLBA BCD Time code word 1 ('JJJSSSSS') | ||
| VLBA BCD Time code word 2 (16 bit) ('.SSSS') | CRC 16 bit | |
Disk Data Format
Raw VLBI data is packed within a 32 bit word, with the earliest time sample corresponding to the least significant bit.
Mark5 control commands
Mark5 Control commands
The Mark5A protocol uses two TCP ports:
- m5data 2630/tcp # Mark5 data
- m5drive 2620/tcp # Mark5 control
Commands are sent to the m5drive port as newline terminated strings. The replies are newline terminated also.
Data is sent to the m5data port.
Mark5 commands
play_rate=data:<rate>
Used to set the output data rate of the Mark5 at the station.
Expected response:
[=!=]play_rate = 0 ;
play=off
Used to make the Mark5 stop playing if it was playing back data from disk.
net_protocol=<protocol>:<sockbuf size>:<workbuf size>
Used to set the network data-transport protocol. The <sockbuf size> argument is the socket send buffer size. You should probably use this value in a setsockopt(…, SOL_SOCKET, SO_SBDBUF, …) call on the socket used to send the data.
Expected response:
[=!=]net_protocol = 0 ;
mtu=<mtu size>
Set the mtu for UDP transfers
Expected response:
[=!=] !mtu = 0 : $mtu bytes;
in2net=connect:<ip>
Used to make the Mark5 at the station connect to the Mark5 at JIVE. The <ip> argument will be the IP address of the Mark5 at JIVE, which should at that point be ready to accept a connection from the Mark5 at the station. The connection should be made to the m5data port. No data will be sent yet.
Expected response:
[=!=]in2net = 0 ;
in2net=on
Used to make the Mark5 at the station start sending data.
Expected response:
[=!=]in2net = 1 ;
in2net=disconnect
Used to make the Mark5 at the station stop sending data and terminate the connection.
Expected response:
[=!=]in2net = 0 ;
in2net=off
??
Expected response:
[=!=]in2net = 0 ;
mode=<data mode>:<data submode>
Used to set the playback mode of the Mark5 at the station.
Expected response:
[=!=]mode = 0 ;
status?
Used to query the status of the (remote) Mark5.
Expected response:
[=!=]status? 0 : 0x00000001 ; (when not sending data)
[=!=]status? 0 : 0x00010001 ; (when sending data)
play?
Request play state (disk only??)
Expected response:
[=!=]status? 0 : 0x00000001 ; (when not sending data)
[=!=]status? 0 : 0x00010001 ; (when sending data)
clock_set=<rate>:int:<rate>
To set the Mark5b clock rate to “rate”
[=!=]clock_set = 0 ;
Setting TVG test
To setup the Mark5 to send the TVG test vector, run:
mode=tvg:8 play_rate=data:4
This will send 8 tracks at 4 Mbps, ie a total of 32 Mbps.
