Table of contents
What is the difference between single buffer and double buffer?
Why is the average time to query a sector 1/2 revolution time
May I ask why you feel sick when you poke your throat?
The analysis process and the process of reading from the system buffer into the user workspace can run in parallel, so the total time is 100.
When data analysis, it can be parallel
So the minimum time is 300
What is the difference between single buffer and double buffer?
Single buffer and double buffer are two different buffer management methods, which are commonly used in operating systems to handle input/output operations. They mainly differ in the number of buffers and how the data is transferred.
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Single buffer:
- Single buffer uses one buffer to store data. Input data is read from the input device into a buffer, and then transferred from the buffer to the destination.
- Data transmission is serial, that is, no other operations can be performed during data transmission.
- Single buffer is suitable for low-speed devices and small data transmission, because other operations will be blocked during data transmission, resulting in low efficiency.
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double buffer:
- Double buffering uses two buffers, one for input data and one for output data.
- Input data is read from the input device into a buffer (input buffer), while data from the output buffer is transferred to the destination. Once the input buffer is full, the data transfer switches to another free output buffer.
- Data transmission is parallel, that is, input and output can be performed simultaneously, which improves efficiency and throughput.
- Double buffering is suitable for high-speed devices and large data transfers, because input and output operations can be performed in parallel, reducing blocking time and waiting time.
In general, the difference between single buffer and double buffer is the number of buffers and the way data is transferred. Compared with single buffer, double buffer has higher concurrency and better performance, but also requires more memory space for storing additional buffers. Whether to choose a single buffer or a double buffer should be weighed and selected according to specific needs and system performance.
Why is the average time to query a sector 1/2 revolution time
The average time to query a sector is 1/2 revolution for the following reasons:
On a disk, data is stored in multiple sectors, and the head needs to be positioned on the disk to read the data of the target sector. Seek time refers to the time required for the head to move from one track to another. This time mainly includes the time for the head to be positioned and stabilized on the target track.
After the head moves to the target track, it needs to wait for the target sector to rotate to the head position. This time is called the rotation delay. Because the disk rotates at a certain speed, the average waiting time is half a disk rotation period.
Since sectors are distributed across different locations on the disk, on average, the time required to query a sector is approximately equal to half a disk revolution. This is an approximate estimate used to simplify calculations and analysis.
Therefore, the average time to query a sector is 1/2 revolution time.
May I ask why you feel sick when you poke your throat?
When you are prodded or poked in the throat area, it may cause a nauseous feeling. This is because there is a nerve called the recurrent laryngeal nerve (Vagus Nerve) near the eye of the throat, which plays an important role in how the body feels and controls the digestive system.
There is a connection between the recurrent laryngeal nerve and the vomiting center and the digestive system. When the recurrent laryngeal nerve is stimulated, it may send a signal of discomfort to the brain, causing a feeling of nausea. The irritation may be physical, such as a poke in the throat, or due to other causes, such as throat inflammation or an allergic reaction.
In addition, the recurrent laryngeal nerve is also involved in the movement of the vocal cords and larynx, so when the larynx is stimulated, it can sometimes cause cough reflex or discomfort in the larynx.
It's important to note that everyone feels and responds differently, so not everyone feels nauseous when their throat is irritated. If you are confused by this condition or have persistent discomfort, it is recommended to consult a doctor for further evaluation and advice.