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Asked: 2026-06-03T21:26:52+00:00

I’m coding a part of little complex communication protocol to control multiple medical devices

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I’m coding a part of little complex communication protocol to control multiple medical devices from single computer terminal. Computer terminal need to manage about 20 such devices. Every device uses same protocol fro communication called DEP. Now, I’ve created a loop that multiplexes within different devices to send the request and received the patient data associated with a particular device. So structure of this loop, in general, is something like this:

Begin Loop
   Select Device i
      if Device.Socket has Data
         Strip Header
         Copy Data on Queue
      end if

      rem_time = TIMEOUT - (CurrentTime - Device.Session.LastRequestTime)
      if TIMEOUT <= 0
         Send Re-association Request to Device
      else
         Sort Pending Request According to Time
         Select First Request
            Send the Request
            Set Request Priority Least
         end Select
      end if
   end Select
end Loop

I might have made some mistake in above pseudo-code, but I hope I’ve made myself clear about what this loop is trying to do. I’ve priority list structure that selects the device and pending request for that device, so that, all the requests and devices are selected at good optimal intervals.

I forgot to mention, above loop do not actually parse the received data, but it only strips off the header and put it in a queue. The data in queue is parsed in different thread and recorded in file or database.

I wish to add a feature so that other computers may also import the data and control the devices attached to computer terminal remotely. For this, I would need to create socket that would listen to commands in this INFINITE LOOP and send the data in different thread where PARSING is performed.

Now, my question to all the concurrency experts is that:
Is it a good design to use single socket for reading and writing in two different threads? Where each of the thread will be strictly involved in either reading or writing not both. Also, I believe socket is synchronized on process level, so do I need locks to synchronize the read and write over one socket from different threads?

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1 Answer

  1. Editorial Team

    There is nothing inherently wrong with having multiple threads handle a single socket; however, there are many good and bad designs based around this one very general idea. If you do not want to rediscover the problems as you code your application, I suggest you search around for designs that best fit your planned particular style of packet handling.

    There is also nothing inherently wrong with having a single thread handle a single socket; however, if you put the logic handling on that thread, then you have selected a bad design, as then that thread cannot handle requests while it is “working” on the last reqeust.

    In your particular code, you might have an issue. If your packets support fragmentation, or even if your algorithm gets a little ahead of the hardware due to timing issues, you might have just part of the packet “received” in the buffer. In that case, your algorithm will fail in two ways.

    1. It will process a partial packet, one which has the first part of it’s data.
    2. It will mis-process the subsequent packet, as the information in the buffer will not start with a valid packet header.

    Such failures are difficult to conceive and diagnose until they are encountered. Perhaps your library already buffers and splits messages, perhaps not.

    In short, your design is not dictated by how many threads are accessing your socket: how many threads access your socket is dictated by your design.

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