GrofLuigi Posted September 16, 2013 Share Posted September 16, 2013 (edited) ...That is, the partition where the BCD resides. I have a specific setup which I don't want to disturb:This is as seen from Windows 7, which is on the second partition (C:). Dual boot is with XP, which is on the first partition, seen here as F: . When XP is booted, letters are reversed (XP, first partition, is C: and Win7, the second, is F:). It works perfectly for me because every OS is "isolated" in its own partition, sees itself as drive letter C: and the BCD is on the Win7's partition. I use custom boot selector/loader (OSL2000) which is the only thing (tiny) inserted into the first sector (or boot sector, or whatever it's called) of the disk.Now, this is an SSD and I want to make the cluster size equal to the NAND page size, which is 8k for this Samsung 840 Pro. The purpose is longevity of the SSD. In many places I have read that this is impossible for Windows 7 (BCD). Is that still so? I don't want to create another partition.I have already enlarged clusters (non-destructively) of the other two partitions from 4k to 8k with Paragon Hard Disk Manager (bootable CD), but when I do it to the Win7 partition, it doesn't boot. Even Paragon says so in the help file. Luckily it was reversable, but of course I still have backups.So, can I do anything? This is the most written to partition here.*Edit: and by the way, all partitions are aligned, and I think the alignment won't be disturbed if I don't resize them. Partitions start at offset:10485761601385267249568284672GL Edited September 16, 2013 by GrofLuigi Link to comment Share on other sites More sharing options...
Tripredacus Posted September 16, 2013 Share Posted September 16, 2013 I know very little about this, so I did some search. Does this help any?I can confirm for you that Windows does not support sector sizes greater than the Memory Manager's page size.Its from here: http://www.osronline.com/showthread.cfm?link=235324The only thing on MS about 8k I can find is refering to DOS.http://support.microsoft.com/kb/67321/en-usI checked that since in that forum thread there is a link to a 4k OS support article, but makes no mention of 8k. Link to comment Share on other sites More sharing options...
jaclaz Posted September 16, 2013 Share Posted September 16, 2013 @TripYep but that is about Physical Sector size (that has nothing actually to do with cluster size).@GrofluigiThere may be issues with the boot code (and just with it).Since you do have some 23 Gb free on that device, you can experiment, making a (temporary) partition using that space.Care to share the source of your opinion of using an 8 Kb cluster being *any* "better"? jaclaz Link to comment Share on other sites More sharing options...
GrofLuigi Posted September 17, 2013 Author Share Posted September 17, 2013 @GrofluigiThere may be issues with the boot code (and just with it).Since you do have some 23 Gb free on that device, you can experiment, making a (temporary) partition using that space.Care to share the source of your opinion of using an 8 Kb cluster being *any* "better"? jaclazThat is some magic free space a Magician from Samsung created for me. Or, in other (big) words, over-provisioning is supposed to reduce write amplification and ensure write consistency. I don't care much about that second part (write consistency), but since the manufacturer recommends overprovisioning and I can afford to lose some space (I have enough), I go with it.If I were to make another (boot?) partition, I'd make it at the beginning of the disk, but I don't want to (for now) since everything is so neat and self-contained.I would like to have 8 Kb clusters because of "write amplification" or, in this case "erase amplification?". Samsung 840 Pro (and every SSD) erases bytes in pages, which in this case is 8 Kb. So in theory, for a file of under 4 Kb in size, it would unnecessarily erase another block of 4 Kb or leave this block "dirty". Or the garbage collection routine would transfer the contents to another block and then erase these two 4 Kb blocks.GL Link to comment Share on other sites More sharing options...
jaclaz Posted September 17, 2013 Share Posted September 17, 2013 I would like to have 8 Kb clusters because of "write amplification" or, in this case "erase amplification?". Samsung 840 Pro (and every SSD) erases bytes in pages, which in this case is 8 Kb. So in theory, for a file of under 4 Kb in size, it would unnecessarily erase another block of 4 Kb or leave this block "dirty". Or the garbage collection routine would transfer the contents to another block and then erase these two 4 Kb blocks.I understand that, I was not-so-sure about that particular SSD having 8 Kb pages (and operating on them as "full pages").In any case - and with all due respect - it seems to me like the idea makes little sense. Let's take two extremes for the sake of reasoning.only 1 (one) file below 4 Kb is in the filesystem several thousands files below 4 Kb are in the filessystemIf #1 the impact of *whatever* is null.If #2 while the impact of the *whatever* may be relevant or noticeable, in order to reduce it you will further reduce the available capacity of the SSD considerably.My suggestion was however to try making a new (smallish partition) (Yes, a "boot" partition) not entirely unlike the one Windows 7 makes on a non-partitioned disk, with just the BOOTMGR and the \boot\BCD and see if you can boot from that one the "main" partition with the 8 Kb sized clusters.Since it is just a test you can use a part of the space you have free (it is not like having 100 Mb less than the current 23.85 Gb will change *anything*).jaclaz Link to comment Share on other sites More sharing options...
GrofLuigi Posted September 17, 2013 Author Share Posted September 17, 2013 New partition will be my last resort...I was asking more if there are any new, or old, or unknown to me (ungoogled by me) methods to "repair" a BCD on non-4Kb partitions. Maybe third-party tools have progressed (I've heard of EasyBCD, and i think there are others), or something might be possible to be hex-edited, but I need to know what...And the reason makes perfect sense (at least in my head, obviously ) when one remembers that SSDs have finite number of writtes.GLI would like to have 8 Kb clusters because of "write amplification" or, in this case "erase amplification?". Samsung 840 Pro (and every SSD) erases bytes in pages, which in this case is 8 Kb. So in theory, for a file of under 4 Kb in size, it would unnecessarily erase another block of 4 Kb or leave this block "dirty". Or the garbage collection routine would transfer the contents to another block and then erase these two 4 Kb blocks.I understand that, I was not-so-sure about that particular SSD having 8 Kb pages (and operating on them as "full pages").In any case - and with all due respect - it seems to me like the idea makes little sense. Let's take two extremes for the sake of reasoning.only 1 (one) file below 4 Kb is in the filesystem several thousands files below 4 Kb are in the filessystemIf #1 the impact of *whatever* is null.If #2 while the impact of the *whatever* may be relevant or noticeable, in order to reduce it you will further reduce the available capacity of the SSD considerably.My suggestion was however to try making a new (smallish partition) (Yes, a "boot" partition) not entirely unlike the one Windows 7 makes on a non-partitioned disk, with just the BOOTMGR and the \boot\BCD and see if you can boot from that one the "main" partition with the 8 Kb sized clusters.Since it is just a test you can use a part of the space you have free (it is not like having 100 Mb less than the current 23.85 Gb will change *anything*).jaclaz Link to comment Share on other sites More sharing options...
jaclaz Posted September 17, 2013 Share Posted September 17, 2013 (edited) I cannot believe that - IF the issue is in the booting only - it can be solved by modifying the \boot\BCD (which AFAIK contains NOT any particular info related to the filesystem and it's cluster size).If you don't want to add a partition, not even temprorarily for the sake of the test) , you can do with a boot floppy image:http://www.multibooters.co.uk/floppy.htmlan image like described can be mapped and chainloaded by grub4dos alright, and it will need not any re-partitioning, while removing the doubt that it is a BOOTMGR issue of some kind, which is a mere (though educated ) guess based on your "it doesn't boot." report (which is not an actual description of what actually happens ).About the "sense", what I was trying to highlight is that the theoretical "increased wear" may happen only on a limited number of cells, since the number of files less than 4 Kb that are often re-written on a "normal" Windows 7 system are very few, maybe the relevance of the issue is "amplified" by any file which is a multiple of 4 Kb but not of 8 Kb? And, call me reckless if you want , according to these:http://www.anandtech.com/show/7173/samsung-ssd-840-evo-review-120gb-250gb-500gb-750gb-1tb-models-testedhttp://www.anandtech.com/show/6328/samsung-ssd-840-pro-256gb-reviewhttp://www.anandtech.com/show/6459/samsung-ssd-840-testing-the-endurance-of-tlc-nandone of those thingies are guaranteed for 5 years and are estimated at around 11 years of duration.By that time we will likely be using Windows 13.4 SP2¼ and 256 Gb will be the space needed for just the bootmanager and configuration file.jaclazP.S.: After all my guess was educated enough:http://www.terabyteunlimited.com/kb/article.php?id=392http://support.microsoft.com/kb/2272294 Edited September 17, 2013 by jaclaz Link to comment Share on other sites More sharing options...
GrofLuigi Posted September 18, 2013 Author Share Posted September 18, 2013 "it doesn't boot." report - I forgot the exact words, they were on a black screen, not terribly scary, but not big friendly letters either. Due to lack of free time, I will suspend my efforts for now and come back to it later.Thank you Jaclaz Link to comment Share on other sites More sharing options...
jaclaz Posted September 18, 2013 Share Posted September 18, 2013 Well, seemingly not much efforts needed, at the light of the Terabyte page, only to try the Windows 8 version of the BOOTMGR.Hard to believe , but after all Windows 8 does have *some* uses. jaclaz Link to comment Share on other sites More sharing options...
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