[Toybox] dd in toybox?

[enh]

On Tue, Jul 9, 2019 at 8:15 PM scsijon <scsijon at lamiaworks.com.au> wrote:
>
>
> On 09/07/19 20:31, Rob Landley wrote:
> >
> >
> > On 7/9/19 2:55 AM, scsijon wrote:
> >>
> >>
> >> On 09/07/19 16:56, Rob Landley wrote:
> >>> On 7/8/19 10:41 PM, scsijon wrote:
> >>>> I was wondering if you would consider adding parts of dcfldd
> >>>> (https://linuxx.info/dcfldd/, https://linux.die.net/man/1/dcfldd and
> >>>> http://dcfldd.sourceforge.net/) rather than having just the ordinary dd 'bits'
> >>>> to your dd implementation if possible?
> >>>
> >>> What specific feature(s) are you asking for?
> >>>
> >>>> I know it's not new, but the extra
> >>>> operands "pattern, textpattern and errlog" at least seem to be somewhat more
> >>>> than just clearly usefull, with maybe the pair "hash and hashwindow" also if
> >>>> possible.
> >>>
> >>> Um...
> >>>
> >>>> dcfldd is a newer version of dccifd, is functionally the same, but in parallel
> >>>> able to calculate checksum using hashing algorithms are MD5, SHA-1 and SHA-2,
> >>>> while it extends partially (by subscription).
> >>>
> >>> This differs from piping it through sha1sum how? Never having used this, it's
> >>> not immediately obvious how or why to...
> >>>
> >>>> Or do you have some other way we can deal with these combined
> >>>> functions easily?
> >>>
> >>> Pipelines? This is why Doug McIlroy suggested the pipe operator somewhere around
> >>> 1973?
> >>>
> >>>     yes "hello" | dd
> >>>
> >>>> And as usual, i'll state that i'm not a coder nowadays, just a builder with a 3d
> >>>> perspective outlook, I can't give you a patch, just an idea for someone to work
> >>>> with. :-)}
> >>>
> >>> Could you give me some usage examples?
> >>>
> >>
> >> ok, this is the usual example given for it,
> >>
> >> dcfldd if=/dev/source hash=md5,sha512 hashwindow=1G md5log=md5.txt
> >> sha512log=sha512.txt \hashconv=after bs=512 conv=noerror,sync split=1G
> >> splitformat=aa of=image.dd
> >
> > tee </dev/source >(sha512sum>sha512.txt) >(md5sum>md5.txt) | split image.dd
>
> OK, maybe i'm just use to doing it that way since I first came across
> dcfldd, if your way works and your happy with it, i'm not going to argue
> that another way is better as there is always more than one way to do
> something.
>
> >
> >> and all done without external pipe, etc. overheads.
> >
> > Is a pipe a significant overhead? (It naturally takes advantage of SMP, for one
> > thing...)
>
> Can be, i've come across iso's that fail to 'play nice' if smp dd'd but
> work ok if set to use a single processor
> >
> >> My normal use though, is for fixing and changing formats in .iso  and .img
> >> files, saves a total rebuild of an iso just to fix a typo, a bane in my life at
> >> least (if not also for others) when a iso and img.gz are just about ready for a
> >> release which is why I would like pattern and textpattern added.
> >
> > Toybox sed should handle binary files?
> >
> ok, haven't tried it for that, something to do when i've satisfactorily
> built my Quirky Thud to release as i've added toybox to that.
>
> > Rob
> >
> Anyway, regards and keep up the good work, you can take it that it's
> much appreciated by quite a few of us.
>
> And as an OT; I wonder how we are going to take to 256bit, weve stepped
> from 4bit>8bit>16bit>32bit>64bit over the decades and now with the Ryzen
> going strong (out and available), there has been some talk on a few
> kernel (not just linux and BSD) related boards of it starting to be
> 'formulated' as the largest of the Ryzen apparently can handle 'it' in
> some format or another. (Apparently 128bit is being skipped.) Sounds
> like the few mainframes still out there are due to dissapear in the next
> few years, and I wonder what's going to happen with the 'cloud' systems.
> Not sure I would want to be a coder then, it might get somewhat messy
> with instruction timing at least.

(i think you've misinterpreted something that was probably talking
about AVX/AVX2/AVX512
[https://en.wikipedia.org/wiki/Advanced_Vector_Extensions]. no more
related to general-purpose register size than is float/double... also,
from the "that's not a knife, _this_ is a knife" department:
https://alastairreid.github.io/papers/sve-ieee-micro-2017.pdf )

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