Shulou(Shulou.com)06/01 Report--

1) dispatch equipment. First of all, look up the piecemeal equipment table (SDT) according to the physical equipment name in the request of DCT, find out the DCT of the equipment, and then according to the equipment shape field in the equipment, you can know whether the equipment is busy. If you are busy, you will hang the PCB of the pleading process on the equipment queue; in your spare time, you will calculate the safety of the equipment assignment according to a certain algorithm, and if you are safe, you will assign the equipment to the pleading process, otherwise the PCB will still be linked to the equipment queue.

2) dispatch the controller. After assigning the equipment to the process of pleading for Icano, go to its DCT to find out the COCT of the controller connected with the equipment, and you can know whether the controller can be busy from the shape field in COCT. If you are busy, you will hang the PCB pleading for the Igamo process on the waiting queue of the controller, and the controller will be assigned to the process in your spare time.

3) dispatch channels. The CHCT of the channel connected with the controller can be found in the COCT, and whether the channel is busy can be known according to the morphological information in the CHCT. If you are busy, the process of pleading for Igamo will be hung on the waiting queue of the channel; the channel will be assigned to the process in your spare time. Only when all three of the above are successful will the distribution of equipment be regarded as a victory. The Iram O equipment can then be started to stop data transmission.

In order to make the distribution of unique equipment more sensitive and improve the winning rate of distribution, it can also be improved from the following two aspects:

Add the independence of the equipment. The process uses the logical equipment name to plead with IWeiO. In this way, the first DCT of this kind of equipment can be found from SDT. If the equipment is busy, look for the DCT of the second such equipment. Only when all such equipment is busy, the process is hung on the waiting queue of this kind of equipment; as long as one such equipment is available, the safety of the distribution of the equipment will be further calculated.

Think about the state of multi-pathways. In order to avoid the "bottleneck" of I / O fragmentation, the multi-channel I / O zero-fragmentation structure is usually used. At this time, the dispatch of the controller and the channel has to be repeated several times, that is, if the first controller (channel) connected by the equipment (controller) is busy, the second controller (channel) should be checked. Only when all the controllers (channels) are busy, the controller (channel) dispatch is counted as a failure, and the process is hung on the waiting queue of the controller (channel). As long as a controller (channel) is available, it can be assigned to the process in bits and pieces.

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