by Andrey Filippov
Since we started to deliver first NC393 series cameras in May we were working on the cameras software – original version was rather limited. While it was capable of serving images/video over the network and recording them on the internal m.2 SSD, it did not have the advanced image acquisition control (through the GUI and programmatically) that was standard for the earlier NC353 series. Now the core functionality is operational and in a month we plan to have the remaining parts (inter-camera synchronization, working with multiple sensors per-port with 10359 multiplexer, GPS+IMU logging) online too. FPGA code is already ported, but it needs to be tested and a fair amount of troubleshooting, identifying the problems and weeding out the bugs is still left to be done.
Fig 1. Four camvc instances for the four channels of NC393 camera
Users of earlier Elphel cameras can easily recognize familiar camvc web interface – Fig. 1 shows a screenshot of the four instances of this interface controlling 4 sensors of NC393 camera in “H” configuration.
by Mikhail Karpenko
Elphel cameras use camogm, a user space application, for recording acquired images to a disk storage. The application is developed to use such storage devices as disk drives or USB drives mounted in the operating system. The Elphel393 model cameras have SATA-2 controller implemented in FPGA, a system driver for this controller, and they can be equipped with an SSD drive. We were interested in performing write speed tests using the SATA controller and a couple of M.2 SSDs to find out the top disk bandwidth camogm can use during image recording. Our initial approach was to try a commonly accepted method of using hdparm and dd system utilities. The first disk was SanDisk SD8SMAT128G1122. According to the manufacturer specification [pdf], this is a low power disk for embedded applications and this disk can show 182 MB/s sequential write speed in SATA-3 mode. We had the following:
~# hdparm -t /dev/sda2
Timing buffered disk reads: 274 MB in 3.02 seconds = 90.70 MB/sec
~# time sh -c "dd if=/dev/zero of=/dev/sda2 bs=500M count=1 && sync"
1+0 records in
1+0 records out
which results in total write speed around 82 MB/s.
by Oleg Dzhimiev