DIGITIZE TO RAM OR FILE? SOFTWARE > INSTRUNET WORLD SOFTWARE (iW) >
instruNet World can digitize directly into RAM memory, or directly into a File on disk, while digitizing in realtime.
Digitize Directly Into RAM if Your RAM is Large Enough
RAM based digitizing is easier, since data in RAM can easily be saved in different file
formats, is easily loaded back into RAM from disk to be saved to disk in another file
format, and supports faster digitizing rates. Due to these advantages, we recommend
digitizing directly To Ram unless, your RAM is not large enough to hold the data. To
do this, set the Digitize Into field to To Ram Buffer, as illustrated above.
Also, when digitizing into RAM, we recommend that you digitize one Scan (set the Number Of Scans field to 1), and then use the Points Per Scan field to determine how long you digitize, as illustrated to the left.
The areas shown to the left and above are both
accessed by pressing the Record tab and then the Setup Button, as noted here.
you digitize multiple scans directly ToRam, data is overwritten in the RAM buffer and
lost. After digitizing into RAM one can press the Save button in the Record page to
save the data in the RAM buffer to disk in the format specified by the File Type field.
To transfer data to another software package, one typically sets File Type to "Text
Merge". This causes a file named "Excel Waveform Data.txt" to be saved to disk that
is easily opened by a spreadsheet, with each channel in its own column. To save RAM
based data in a compact fast format, we recommend "Binary Merge". To calculate the
amount of RAM used to hold your data, mulitply the number of points, by the number of
channels, by 4bytes-per-point. For example, 3 channels of 10K points each would
consume 120KBytes of RAM (120KB = 4 * 3 * 10000).
directly To File for big data, yet figure out how you are going to process
that huge file on disk before you digitize.
Digitizing directly To File is a quite different. Here, you can have many scans
(e.g. set Number Of Scans field to 10000), and the amount of data that is digitized is limited
by the amount of free space on disk. To do this, set the Digitize Into field to To File, and set the File Type field to Binary Merge. Then, when the Start
button is pressed in the Record page, it will prompt you for a file name before digitizing,
and send the data directly to disk. The main issue, when digitizing directly To File is, "How are you going to deal with all that data on disk?". instruNet World will not allow
you to load it into ram (since file based data is typically too large to fit into ram) and
then save it back out in another file format. It will only allow you to scroll though and
view the data (it automatically pages in segments from disk, as needed, for display).
And to digitize To Disk quickly, you need to use the Binary Merge File Type, which
interlaces all channels into one file, in 32bit floating point form. There is physically no
other way to spool to disk at fast rates without saving in this manner. Therefore, to
process a large disk based stream, one typically needs a software package that
interprets 32bit floating point interlaced data. For details on this file format, please see
File and RAM Buffer Size Limitations
For details on maximum file and RAM buffer sizes, click