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A comment on With 'The Machine,' HP May Have Invented a New Kind of Computer. Parent comment

Re:With 'The Machine,' HP May Have Invented a New Kind of Co... by sp332 on Wednesday June 11, 2014 @02:57PM (#7879762)
It's a lot of unnecessary copying. The data is already in RAM, but you "save" it to a different RAM location, in the RAM disk. Or if you do all your work directly on the file in the RAM disk, you have to deal with filesystem overhead constantly.
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Re:With 'The Machine,' HP May Have Invented a New Kind of Co... by colanderman on Wednesday June 11, 2014 @04:10PM (#7880144)
Or if you do all your work directly on the file in the RAM disk, you have to deal with filesystem overhead constantly.

Not so. Take a look at the Linux kernel implementation of memory-mapped ramdisk files. There is no "filesystem overhead". Zero. The kernel pretty much sets up the page mapping and then is hands-off.

Even if your memory mapping is backed by a file on a block device, the only overhead is occasional paging to disk. This happens on the order of SECONDS… not "constantly"!

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Re:With 'The Machine,' HP May Have Invented a New Kind of Co... by sp332 on Wednesday June 11, 2014 @05:06PM (#7880443)
That's assuming you already have a file and know how big it should be. Or does it take the whole space for one file, and every program on the computer shares the space?
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Re:With 'The Machine,' HP May Have Invented a New Kind of Co... by colanderman on Wednesday June 11, 2014 @07:45PM (#7881081)
Files can be both sparsely and dynamically allocated.
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Re:With 'The Machine,' HP May Have Invented a New Kind of Co... by AnthonyMouse on Wednesday June 11, 2014 @06:29PM (#7880812)
You save things to persistent storage because you want the copy. In the large majority of cases the format on the filesystem is different from the format in memory because the file format is meant to be more readable by humans or by machines with a different endianness or pointer size etc., whereas data in memory is binary and platform-specific to optimize for fast access by the local machine. The benefit of that distinction doesn't go away just because you make the persistent storage faster.
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