HP B8C95AA Manuel d'utilisateur télécharger pdf (Page 98)

HP Designjet T Series — Service Manual 2-38

Appendix A: How to troubleshoot SE 79:04

These errors will most likely only happen in very specific corner cases that

have not been identified during the development or the qualification of the

printer, so normally, they do not severely impact the customer, as they do not

affect their regular working flows.

Symptoms

The symptoms here are as numerous as the number of possible interactions

betw

een the user and the printer. In any case, it’s possible to identify the

steps that caused the error to occur and avoid them as the steps will always

be the same with no variance.

Important: An major element in determining the error is what the state the

er was in at the time the error was displayed. Actions the user has made

when the printer is drying for example can produce an error, whereas the

same action when the printer is doing something else (or is idle) may not

produce any errors.

Solutions and workarounds

The recommended action plan in these cases is to identify the previous steps

that ca

sed the error and:

1 Escalate the issue to the GBU through the GCC in order to have it corrected

the firmware.

2 Recommend to the customer that they try to avoid the same steps to prevent

the is

sue

3 If the conditions that cause the error are in the customer’s regular workflow,

y to identify a different way of achieving the same result out of the printer.

Random SE79:04: Concurrence issues and memory leaks

Some 79:04 errors happen randomly when the printer is being heavily used.

wever, it’s impossible to find a single set of conditions that reproduce the

problem. It just happens from time to time, without a defined pattern.

These random 79:04 can have two different types of root causes:

 Memory leaks: before a program is executed, it allocates the memory it

will need. After the execution is complete, the allocated memory is freed

to be used by other programs. If the allocation or the release of the

memory are not properly programmed, every time the program is

executed some memory will be incorrectly labeled (either as used or as

free). This is known as a memory leak. When a program with a memory

leak is executed a lot, the memory becomes progressively full (since it is

not properly freed). When the leak becomes too big, the printer is left ‘out

of memory’ to execute new processes and a 79:04 is triggered

 Concurrence issues: there are certain resources that can be accessed by

multiple programs or by multiple executions of the same program (what is

known as multiple threads). Access to these resources must be correctly

controlled to prevent unexpected behavior. Issues caused by an incorrect

control of these resources are concurrence issues.

In the following you have a simple example: let’s imagine that there is a

counte

r that controls the communication between the JetDirect card and the

printer’s firmware. Whenever a new packet of information is sent by the

JetDirect card to the printer, the counter increases. When the printer receives

the packet and processes it correctly, the counter decreases. Another process

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HP B8C95AA Manuel d'utilisateur Page 98

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HP B8C95AA Manuel d'utilisateur Page 98

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