RAM image of DVD?
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There are lots of tools to create ISO image files on harddisk from a physical CD/DVD. But are there drivers available (Windows 7 or 10) for reading a raw, physical CD/DVD, sector by sector (i.e. independent of any file system structure) into RAM, providing a driver interface so that software will see it as if it were a physical CD/ROM drive? Alternately, but not as convenient for me: A driver making an ISO file appear as a physical drive rather than as an NTFS file. I don't need that permanent ISO image file, and waiting for it to be created will be a lot slower. (Actually, in my case, the RAM image could be built lazily: The application program could start immedately, and when the driver receives a request for a sector not yet read in, it could freeze the ongoing complete reading, serve the application by accessing the physical disk, and then return to the task of creating a RAM image of the complete disk.) My PC, like most modern PCs today, has 16 Gbytes of RAM, so even a completely packed, two-layer DVD leaves between 6 and 7 GBytes RAM for other applications. If you need more, paging may throw out unused blocks to disk. Keeping a full DVD in RAM is perfectly realistic nowadays. (In the good old days of DOS and 16+4 bit addressing, but RAM sizes were growing beyond 1 Mbyte, we did things like this with floppies: There was software to create a RAM disk in extended memory (who are old enough to remember LIM EMS? :-)). We created an 1.44 Mbyte RAM disk, copied in a entire floppy to it, in one go, track by track. If my memory is right, reading an entire track required two rotations, but after 154 rounds, for 77 tracks, the entire floppy was available thousands of times faster than reading the physical unit. The problem today is not the ISO image file; I can write my own software to access every block in that image. Some other tools read from CD/DVD interfaces, rather than from the NTFS file system, or they provide other functions when reading from a physical drive. So I need a driver to fool them to believe that either an ISO file, or preferably, a RAM image of a disk, really is a physical drive, providing all those operations a physical drive offer, but at RAM speeds. Which software is available to do give me that?
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There are lots of tools to create ISO image files on harddisk from a physical CD/DVD. But are there drivers available (Windows 7 or 10) for reading a raw, physical CD/DVD, sector by sector (i.e. independent of any file system structure) into RAM, providing a driver interface so that software will see it as if it were a physical CD/ROM drive? Alternately, but not as convenient for me: A driver making an ISO file appear as a physical drive rather than as an NTFS file. I don't need that permanent ISO image file, and waiting for it to be created will be a lot slower. (Actually, in my case, the RAM image could be built lazily: The application program could start immedately, and when the driver receives a request for a sector not yet read in, it could freeze the ongoing complete reading, serve the application by accessing the physical disk, and then return to the task of creating a RAM image of the complete disk.) My PC, like most modern PCs today, has 16 Gbytes of RAM, so even a completely packed, two-layer DVD leaves between 6 and 7 GBytes RAM for other applications. If you need more, paging may throw out unused blocks to disk. Keeping a full DVD in RAM is perfectly realistic nowadays. (In the good old days of DOS and 16+4 bit addressing, but RAM sizes were growing beyond 1 Mbyte, we did things like this with floppies: There was software to create a RAM disk in extended memory (who are old enough to remember LIM EMS? :-)). We created an 1.44 Mbyte RAM disk, copied in a entire floppy to it, in one go, track by track. If my memory is right, reading an entire track required two rotations, but after 154 rounds, for 77 tracks, the entire floppy was available thousands of times faster than reading the physical unit. The problem today is not the ISO image file; I can write my own software to access every block in that image. Some other tools read from CD/DVD interfaces, rather than from the NTFS file system, or they provide other functions when reading from a physical drive. So I need a driver to fool them to believe that either an ISO file, or preferably, a RAM image of a disk, really is a physical drive, providing all those operations a physical drive offer, but at RAM speeds. Which software is available to do give me that?
Couldn't tell "why" you are going down this road. I thought that if one wanted to have a "faster disk" these days, one would use an SSD. My SSD is 256GB (small); on the motherboard; and boots / shuts Windows 10 Pro in "no time at all". But then again: [12 Free RAMDisk vs SSD - Ten Times Faster Read and Write Speed via RAM Virtual Disk | GeckoandFly 2018](https://www.geckoandfly.com/21507/ramdisk-virtual-disk-memory/)
"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal
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Couldn't tell "why" you are going down this road. I thought that if one wanted to have a "faster disk" these days, one would use an SSD. My SSD is 256GB (small); on the motherboard; and boots / shuts Windows 10 Pro in "no time at all". But then again: [12 Free RAMDisk vs SSD - Ten Times Faster Read and Write Speed via RAM Virtual Disk | GeckoandFly 2018](https://www.geckoandfly.com/21507/ramdisk-virtual-disk-memory/)
"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal
Maybe I wasn't clear enough. I've got data on a DVD disk - or rather: A number of them. I've got an analysis program reading the data on the disks, but it will read from a physical disk only. It will not read from a disk file, neither on flash nor magnetic disks. I do not produce the data; I receive and analyze them. It is more or less a one-time operation. Even if I could make an ISO file before I start the analysis, as soon as the analysis is done, I would delete the ISO file; I would not retain it, neither on a magnetic or flash disk. RAM access is a lot faster than even flash disks, even with the OS caching disk blocks accessed. But more important: Creating an ISO image file on a flash or magnetic disk as a precursor to the analysis takes time. Especially if the driver would let you start working immediately after the DVD disk has been inserted, essentially reading the data sequentially in the most efficient way but if you refer to data not yet read in would put the sequential reading on hold to serve your request before continuing, the total time from start to completion could be a lot less. Those alternatives in the article you link to will do half the job: Putting data in RAM. But the other half is having it appear not as an NTFS or FAT disk, but as a physical device that can be read as a raw DVD disk, below the file system layer. None of the 12 alternatives claim to mimic a physical DVD interface, and will not be accessible to an analysis program that reads from such interfaces only.
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Maybe I wasn't clear enough. I've got data on a DVD disk - or rather: A number of them. I've got an analysis program reading the data on the disks, but it will read from a physical disk only. It will not read from a disk file, neither on flash nor magnetic disks. I do not produce the data; I receive and analyze them. It is more or less a one-time operation. Even if I could make an ISO file before I start the analysis, as soon as the analysis is done, I would delete the ISO file; I would not retain it, neither on a magnetic or flash disk. RAM access is a lot faster than even flash disks, even with the OS caching disk blocks accessed. But more important: Creating an ISO image file on a flash or magnetic disk as a precursor to the analysis takes time. Especially if the driver would let you start working immediately after the DVD disk has been inserted, essentially reading the data sequentially in the most efficient way but if you refer to data not yet read in would put the sequential reading on hold to serve your request before continuing, the total time from start to completion could be a lot less. Those alternatives in the article you link to will do half the job: Putting data in RAM. But the other half is having it appear not as an NTFS or FAT disk, but as a physical device that can be read as a raw DVD disk, below the file system layer. None of the 12 alternatives claim to mimic a physical DVD interface, and will not be accessible to an analysis program that reads from such interfaces only.
I'm still not "clear" then. This tool will let you mount image files of hard drive, cd-rom or floppy, and create one or several ramdisks with various parameters. This all-in-one package includes the ImDisk Virtual Disk Driver (2.0.9), the DiscUtils library that extends the number of supported image file formats, and adds several GUIs and features. (The "cd-rom" option includes "DVDs") From there, there are virtual machines. If not, more "cpu" / threads. Where you see obstacles, I see options.
"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal
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I'm still not "clear" then. This tool will let you mount image files of hard drive, cd-rom or floppy, and create one or several ramdisks with various parameters. This all-in-one package includes the ImDisk Virtual Disk Driver (2.0.9), the DiscUtils library that extends the number of supported image file formats, and adds several GUIs and features. (The "cd-rom" option includes "DVDs") From there, there are virtual machines. If not, more "cpu" / threads. Where you see obstacles, I see options.
"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal
OK, so I have a DVD-ROM from which I can create an image file, aka "ISO file", residing on my harddisk / flash disk. This image file I can mount as RAMdisk so that I can access the files on that DVD-ROM as if it was a physical NTFS or FAT file system. The text you quote states that the ISO file may be an image of a hard drive (with an NTFS or FAT file system), or a CD-ROM (with an ISO 9660 file system or derivatives) or floppy (with a FAT file system). Although the file system within that image file reside in RAM structures, read in from a single file created from a harddisk, CD-ROM or floppy, it will appear to file system requests as if it was a disk with an NTFS, ISO 9660 or FAT file system, with directories and format restrictions etc. I see no indication whatsoever in the description that it allows direct access to physical sectors, or that it support device control for emulating physical drives. If it did, I am quite sure that it would be seen in the documentation. Maybe ImDisk - in the good old "if it doesn't do what you want, modify it yourself" Open Source style - can be modified to appear as a physical CD/DVD drive with no implied file system structure, but providing a raw access to the sectors, and reacting sensible to all control signals that might be sent to a physical CD/DVD drive. If my task were to write drivers, I could probably do that. I did write a few driver in the DOS days; I never did for Windows. If you have tried using ImDisk yourself, using some DVD/CD software accessing the RAM image as a physical drive - e.g. trying to burn files to the RAM disk as a CD-RW disk, ejecting the disk, responding to drive capabilites etc. - then you know better than I do. But then you probably would not refer to a description of functionality that is not what I am after.
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OK, so I have a DVD-ROM from which I can create an image file, aka "ISO file", residing on my harddisk / flash disk. This image file I can mount as RAMdisk so that I can access the files on that DVD-ROM as if it was a physical NTFS or FAT file system. The text you quote states that the ISO file may be an image of a hard drive (with an NTFS or FAT file system), or a CD-ROM (with an ISO 9660 file system or derivatives) or floppy (with a FAT file system). Although the file system within that image file reside in RAM structures, read in from a single file created from a harddisk, CD-ROM or floppy, it will appear to file system requests as if it was a disk with an NTFS, ISO 9660 or FAT file system, with directories and format restrictions etc. I see no indication whatsoever in the description that it allows direct access to physical sectors, or that it support device control for emulating physical drives. If it did, I am quite sure that it would be seen in the documentation. Maybe ImDisk - in the good old "if it doesn't do what you want, modify it yourself" Open Source style - can be modified to appear as a physical CD/DVD drive with no implied file system structure, but providing a raw access to the sectors, and reacting sensible to all control signals that might be sent to a physical CD/DVD drive. If my task were to write drivers, I could probably do that. I did write a few driver in the DOS days; I never did for Windows. If you have tried using ImDisk yourself, using some DVD/CD software accessing the RAM image as a physical drive - e.g. trying to burn files to the RAM disk as a CD-RW disk, ejecting the disk, responding to drive capabilites etc. - then you know better than I do. But then you probably would not refer to a description of functionality that is not what I am after.
Sorry, I just thought you were stuck in the weeds. Last time I looked at sectors, it was using "Norton Utilities" on DOS x.x ... and I cannot even remember why. I guess that's why my mind is going blank listening to you explain why you need to operate at the "sector level" when there are better ways to spend one's time in relation to the current state of the art.
"(I) am amazed to see myself here rather than there ... now rather than then". ― Blaise Pascal
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There are lots of tools to create ISO image files on harddisk from a physical CD/DVD. But are there drivers available (Windows 7 or 10) for reading a raw, physical CD/DVD, sector by sector (i.e. independent of any file system structure) into RAM, providing a driver interface so that software will see it as if it were a physical CD/ROM drive? Alternately, but not as convenient for me: A driver making an ISO file appear as a physical drive rather than as an NTFS file. I don't need that permanent ISO image file, and waiting for it to be created will be a lot slower. (Actually, in my case, the RAM image could be built lazily: The application program could start immedately, and when the driver receives a request for a sector not yet read in, it could freeze the ongoing complete reading, serve the application by accessing the physical disk, and then return to the task of creating a RAM image of the complete disk.) My PC, like most modern PCs today, has 16 Gbytes of RAM, so even a completely packed, two-layer DVD leaves between 6 and 7 GBytes RAM for other applications. If you need more, paging may throw out unused blocks to disk. Keeping a full DVD in RAM is perfectly realistic nowadays. (In the good old days of DOS and 16+4 bit addressing, but RAM sizes were growing beyond 1 Mbyte, we did things like this with floppies: There was software to create a RAM disk in extended memory (who are old enough to remember LIM EMS? :-)). We created an 1.44 Mbyte RAM disk, copied in a entire floppy to it, in one go, track by track. If my memory is right, reading an entire track required two rotations, but after 154 rounds, for 77 tracks, the entire floppy was available thousands of times faster than reading the physical unit. The problem today is not the ISO image file; I can write my own software to access every block in that image. Some other tools read from CD/DVD interfaces, rather than from the NTFS file system, or they provide other functions when reading from a physical drive. So I need a driver to fool them to believe that either an ISO file, or preferably, a RAM image of a disk, really is a physical drive, providing all those operations a physical drive offer, but at RAM speeds. Which software is available to do give me that?