On 24 Dec 2020 at 13:10, ZB wrote: > On Tue, Dec 22, 2020 at 02:37:44PM +0100, DosWorld via Freedos-user > wrote: > >> 1. This is bad idea - use flash cards for swap or more modern os >> (like all windows). I had experience with 16 TF cards, which die >> after 1 year (rewrite limit). All 16 cards work in non-overloaded >> machines. > > My CF card is used as "HDD" 3rd month - we'll see in 9 months will > it survive. > > I doubt it "must die" after a year of use - consider all that > photocameras that use CF cards; their owners probably had to buy new CF > cards each year. > Practical experience, using CF cards as a boot drive in "miscellaneous embedded/industrial" computers where the OS and disk don't have much to do:
A) standard desktop Windows (XP or earlier) with swapping left operational, 1 year of lifetime sounds about right. B) Windows Embedded (XP or later) with swap turned off and preferably with the drive operated in read-only mode (Write Filter enabled): the CF card would live forever. Note that if you need to use the flash drive as a swap medium, with SLC you have roughly 20 times the lifetime, compared to MLC. But it's generally advisable to avoid swapping altogether. Also think about logging, Windows updates etc. We've also seen MLC CF cards die after 3 months, when used as the system drive in a SCADA machine, where the software kept making a backup of the current "state" as often as it could (writing a chunk of data to a file on the flash a couple times per second, apparently). Swapping means writing tiny transactions (4 kB) at random offsets, which practically means that the dual-stage mapping mechanism to flash rows and erase blocks will have a lot of janitoring to do. This will multiply the volume written. Compared to that, photoes are stored in pretty much sequential fashion (JPEG's, each several MB in size) and there are not nearly as many of them as the number of writes coming from Windows that keep running 24x7. How many photoes can a human shoot - a couple dozen a day? A couple hundred? When using smal flash form factors as boot drives (CF, similar IDE Flash "plugs" or SD for instance, CFast, mSATA or M.2), avoid wishful thinking. And, 2.5" Flash SSD's are not necessarily better. I'm speaking machines for business/industrial use. If this is a toy machine, you probably have your own idea :-) >> 2. Use last generation of motherboard for Pentium-1 (as minimum) >> with VIA Apollo chipset (designed for Pentium and Amd K6/K6-2) - >> only this chipset understand ATA100 native and allow connect CF >> via simple IDE-CF reductor > > I use that CF card with old 486 Soyo-SiS mobo (and the "simple > reductor"). > >> (intel VX/HX - NO). As i understand, problem is - no support >> ATA100 in older IDE-controllers. In other case, you need use >> PCI-IDE cards or special modern ISA-IDE controllers (designed >> specially for use with CF). > > I use that CF card with old VLB IDE controller. Seems to be working > just fine, the only problem is 2 GB limit; it can't "see" any larger > partition. > Anyway it's not related to CF card, but to controller rather > CF cards are generally backwards compatible with the old PIO modes (DMA-less transfers, polling for every single byte). Thus, in theory, they should work against any old IDE controller. A CF card that supports UDMA100 should run just fine in a system that can only do PIO, or run limited to UDMA33 for instance. As for size limits, I agree that some BIOSes did actually have such a limit in the past. It doesn't seem to be an inherent limit of IDE/ATA or LBA28 (those have other limits of their own). Other than that, 2 GB is a limit of FAT16, per volume = not necessarily a BIOS issue. Though I cannot rule out that a particular BIOS would in fact inspect the partition table and would not approve of partitions larger than some arbitrary size :-) Over the years, I've seen various "innovative BIOS heuristics" in the boot sequence. http://www.dewassoc.com/kbase/hard_drives/hard_drive_size_barriers.htm https://tldp.org/HOWTO/Large-Disk-HOWTO-4.html https://en.wikipedia.org/wiki/Comparison_of_file_systems And another matter is that, especially in the old days, the ATA flash target controllers (and their firmware) were not as universally compatible with various IDE hosts as were the magnetic disk drives. Over the years, Intel has crystallized as the dominant brand in terms of ATA HBA ports sold, and thus, every ATA Flash maker tested against Intel first and foremost, but hardly against any other vendor's HBA's... thus, it is not uncommon to find flash drives that work with Intel IDE HBA's but have a problem against particular lesser brands of chipsets. I have sympathy for your hardware archaeology :-) Frank _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
