Is there a define number of harddisk capacity in QNX6.2.1?

I installed QNX6.2.1 in my computer today, and there was a 160G hard disk. Originally I have a WinXP, but when I finished I found some hard district disappeared. That was strange, I thought. Thank to god, my data have been backuped. I fdisked them, then I tried to QNX, but there was message in the screen when startup QNX: “fk-fail”.

Now, I guess QNX6.2.1 maybe have a small “largest capicity number of its harddisk”. Could some one told me yes or no? and the number for better.


Is WinXP SP2? I had a 160Gig HD with WinXP SP 1, and when I wrote beyond the 120Gig point, it wrote to the beginning of the drive, ruining it. QNX does not do this.

Don’t know about 6.2.1, but 6.3 is happy on a 300G HD. I think the limit is beyond current HD size ;-)

The QNX file system hasn’t changed much since QNX 4. The original QNX 1/2 file system was built fairly short sighted, so when then built the QNX 4 system, they were careful to make sure it would not be limited for quite a while. I think there may have been some ATA interface issues, but I thought they were fixed by 6.2.1. The big limitation right now is the 2Gig file size.

In manual /QNX Neutrino RTOS/User’s Guite/Understanding System Limits it says

  • Filesystem size if 2G * 512 . That means a partition can’t be bigger then 1 Terabyte.

Disk size is 2 exponent 64. But given there can’t be more then 4 partitions of 1 Terabyte each, that means the maximum is 4Terabytes. Hum we are not that far away from 4 Terabytes disk…

Well, then the QNX 4 file system held up for over 10 years. Not really bad if you think about it. One might argue that even though Terabyte disks are available, and 4Tera will come eventually, how many QNX systems require this. Even then, such users might be better off with an upscale NFS. So my guess is they can live with the problem for another 6 years.

Once they fix the 2G limitation that should take care of the 1Terabyte limitation as well. The 2G limits is perventing the bitmap file from being bigger then 2G.)

However i though it was possible to set the block size to 1024 which then raise the limit to 2Tera bytes per partitions ( in theory)

As a matter of fact I wouldn’t mind using blocks of 4096 bytes for potential improvement of disk performance, that would raise the limit to 16 Terabytes per partitions.

Yes, the only downside to 4096 blocks is if you happen to have an enormous number of small files. The ratio of 1 Terabyte to 512bytes in a sector is about 2 Billion to one. While we are used to billions of memory bytes and billions of disk bytes, billions of files is a whole different animal. Imagine for a second that you had a billion photos, and you looked at each for 5 seconds, how long would that take?