Design query
Evening all
I have a fairly basic design query and I woz wondering if anyone could help/come up with ideas/ laugh at it
The application is a data transfer application for sending programs from a windoze based pc to expensive industrial machinery
The application is designed to download files to the computers serial port, with a queue facility in order that the user can select mulitple files to download, the queue is needed because it takes forever to download a 400K file via a serial port running at 4800 baud, or even 9600 baud
no problem so far, Ok
Question 1. whats the best form of preventing a write operation to a file after its been added to the queue?I'm thinking I dont want someone to alter a file thats going to be downloaded , basically for safety reasons
Additional read operations on a file are not a problem ie, sending the same data to multiple serial ports
Question 2. the application in question is able to write to either COM1 or COM2 and can have a download running on each port concurrently. whats the best way of arranging the queue? have one queue object, or have multiple queue objects , each one tied to a serial port ?
The other problem is the occurance of a system crash (usually caused by my boss turning the PC off because he's a pillock), would writing the queue objects to disk after every queue operation be a good idea, so that when the system reboots, it can see if there are any queues waiting to be processed.
Boris
Question 3 . will this thing ever make me more money?
