But this means that 1 byte file will use 32Kb of hard disk space

I tried qubata v.3.01 on ROM but my old Qubide Hard Disk (created
with qubide rom 2..01) didn't boot
The Hard Disk is a 512Mb drive with 4
partitions of about 120Mb.

If I reinstall 2.01 ROM all run well.


Andrea Carpi

Il 23.07.2017 20:12 Alain HAOUI via Ql-Users ha

> For qubide with driver qubata v3.x the max file size
supported may be 2 gigabytes minus some data structure kilobytes,
provided you have created a suitable big partition with 64 sectors per
> This is the maximum under qdos with 2 words indexes when used
as unsigned.
> Regards,
> Alain
> -----Message d'origine-----
> De :
"Jan Bredenbeek via Ql-Users" 
> Envoyé : ‎23/‎07/‎2017 17:21
> À :
"ql-us...@q-v-d.com [2]" 
> Objet : Re: [Ql-Users] Maximum length of
files on QL file-system
> On 23 July 2017 at 15:47, Andrea Carpi via
Ql-Users <
> ql-users@lists.q-v-d.com [4]> wrote:
>> Hello everybody
Trying to transfer large files between Windows 10, QPC2, and
QL-Aurora-SGC-Qubide I have noticed that there are big limitations in
the maximum length of the files. I mean: - On QXL.WIN hard drive in QPC2
I'm not able to generate files longer than 50Mb (End Of file error) - On
the Qubide hard drive the limit is 19Mb (ROM 2.01), but perhaps also
depends on the partition creation choices - On Ram Disk (in QPC2 maximum
RAM 128 Mb) I did not find any limits unless the size of the RAM - I did
not find limits on DOS devices from QPC2 except those of the file system
in use on Windows (NTFS) Specifically for QXL.WIN and QUBIDE do anyone
know the exact length limits and why?
> The QDOS file system stores
the file position in the channel definition
> block as two 16-bit words
- one for the block number and one for the byte
> position within one
block. So, when using 512-byte blocks, the maximum file
> length will be
65535*512 bytes or just under 32MB (or 16MB when using
> signed
arithmetic). When using 2K byte blocks, the limit will be 128 or
> 64MB
> I know mdv and flp use 512-byte block size and ED flp
have 2K byte sectors
> but I'm not sure if the latter also uses 2K
blocks. The same goes for
> (virtual) win drives - sectors are usually
grouped to keep the map within
> limits but I don't know off-hand if
that also affects the block size (it
> might as well be 512 bytes,
depending on the driver).
> This use of word-sized block numbers
within QDOS is an unfortunate design
> flaw - as is the standard
FS.MDINF trap which returns word-sized sector
> counts - but could TT
back in 1984 foresee that within five years there
> would be a storage
medium for the QL that surpassed the 32MB limit? In the
> PC world there
are multiple examples of this - remember the 32MB partition
> size limit
in DOS 3.3, then the 528MB limit on CHS-addressed hard disks,
> and the
initial 128GB limit on LBA which was supposed to 'fix' CHS.
> Storage
capacity has grown so much that any 'X MB ought to be enough for
everybody' design decision has proven wrong eventually...
> -- *Jan
Bredenbeek* | Hilversum, NL | j...@bredenbeek.net [5]
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