Chapter 2
NI 5450 Overview
NI PXIe-5450 User Manual
2-54
ni.com
Memory Fragmentation
When storing multiple waveforms in NI 5450 memory, fragmentation can
become a problem. Both waveforms and instructions are stored in NI 5450
memory in contiguous blocks. These blocks are allocated in multiples of
128 bytes, and they are written in the order that you configure them.
Fragmentation occurs when you delete a waveform or script from memory
that was not the last block written.
Every new NI-FGEN session begins with empty memory. First, multiple
waveforms are written to memory, nearly filling the device memory, as
shown in the following diagram.
If you now try to write Waveform 5 (shown in the following figure) to the
device, you find there is not enough memory. To make room for the
waveform, you could delete Waveform 3 to create enough space in memory
for Waveform 5.
W
a
veform
2
W
a
veform
1
W
a
veform
3
W
a
veform
4
S
e
qu
ence
In
s
tr
u
ction
s
Free
Memory
W
a
veform
4
W
a
veform
5
Free
Memory
W
a
veform
2
W
a
veform
1
S
e
qu
ence
In
s
tr
u
ction
s
Free
Memory
