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Groups > comp.os.linux.misc > #37284
| From | "Carlos E.R." <robin_listas@es.invalid> |
|---|---|
| Newsgroups | comp.os.linux.misc |
| Subject | Re: Zip list |
| Date | 2023-02-26 20:22 +0100 |
| Message-ID | <85oscjxves.ln2@Telcontar.valinor> (permalink) |
| References | (10 earlier) <tst07u$cgst$2@dont-email.me> <sse9cjx79g.ln2@Telcontar.valinor> <ZPWdnYAQdIm6P2T-nZ2dnZfqn_SdnZ2d@earthlink.com> <lt6pcjxblu.ln2@Telcontar.valinor> <tq-cnUzR9u6bfmf-nZ2dnZfqnPudnZ2d@earthlink.com> |
On 2023-02-26 05:41, 25A.I866 wrote:
> On 2/25/23 6:10 AM, Carlos E.R. wrote:
>> On 2023-02-25 06:51, 25A.I866 wrote:
>>> On 2/19/23 6:48 AM, Carlos E.R. wrote:
>>>> On 2023-02-19 12:13, The Natural Philosopher wrote:
>>>>> On 18/02/2023 21:18, Andreas Kohlbach wrote:
>>>>>> On Sat, 18 Feb 2023 13:15:31 +0000, The Natural Philosopher wrote:
>>>>>>>
>>>>>>> On 18/02/2023 11:43, Carlos E.R. wrote:
>>>>>>>> On 2023-02-18 11:12, The Natural Philosopher wrote:
>>>>>>>>>
>>>>>>>>> RAR was my pet hate...
>>>>>>>>>
>>>>>>>> Why? :-? :-o
>>>>>>>>
>>>>>>> Could never find an unpacking program that ran on Unix.
>>>>>>
>>>>>> unrar x file.rar
>>>>>>
>>>>>> should deflate the content into the PWD.
>>>>>
>>>>> Today yes, not in 1993, to run on SCO Unix.
>>>>
>>>> Well, RAR for DOS appeared on 1993! :-D
>>>>
>>>> So in 1993 there wasn't a version for Linux, either.
>>>>
>>>> I believe the sources were published with version 2, or version 2
>>>> sources were published when version 3 appeared. The wikipedia
>>>> article doesn't have dates for these. But as soon as those sources
>>>> appeared, anybody could compile a version for Unix.
>>>
>>>
>>> Always SOUNDS so simple :-)
>>>
>>> I always wind up having to write fill-ins for the
>>> missing/very-different library routines between
>>> Win and Lin.
>>>
>>> Anyway, I'm not sure about the fascination with RAR.
>>> It is good, but then so are many others that are more
>>> modern/portable/supported.
>>>
>>> Found an interesting "loop-based" approach to an Str2Int64()
>>> today. Basically it does powers of ten on each digit (derived
>>> from the ASCII values of the digits minus-48). It MAY be a bit
>>> faster than the one I wrote the other day for Pascal that
>>> involves 'shrinking down' the presented number. I'll have
>>> to benchmark. Mine only used integer subtraction and ONE
>>> modulo. Not AS many steps. But, we'll see.
>>>
>>> I was writing a "disk visualizer" the other day (turned out
>>> pretty well) but Int64 numbers/functions ARE involved. Today
>>> I took that to write a 'C' "Disk Blaster" ... kinda like using
>>> 'dd' to zero (or pattern-write) a whole drive but because it's
>>> not as complex it's about 30% quicker. Added a 'skitter' option
>>> that's applied AFTER the prescribed number of bytes are
>>> overwritten ... 'skittering' means writing yer zero/pattern
>>> block roughly (a little randomness added to annoy) every
>>> 50mb on the REST of the disk area. It is not 'erasure'
>>> per-se, but kinda 'corrupts' and is 50x as fast. You can
>>> go thru a 1tb disk in an external USB3.0 fixture in about
>>> five minutes with 'skittering'. So, you totally obliterate
>>> the X-bytes you're most paranoid about and then randomly
>>> insert junk in the rest.
>>>
>>> Just gotta smooth-out the params ... there's no slack
>>> right now. Something like 'dd' params would be good.
>>> It always uses the equiv of "bs=1M" ... seems the best
>>> compromise after some experimentation. My visualizer
>>> made it easy to see if the blaster util was doing it
>>> right.
>>
>> I wrote a tool in pascal to write an entire device with nearly random
>> data, and does so at the SATA speed of the (mechanical) disk, about
>> 190 MB/S last time I tried. I have done 4 TB disks.
>
>
> Free Pascal (I love Pascal) can indeed write an entire
> terabyte disk full of zeros or whatever. However what
> I discovered is that their "seek" function - despite
> docs to the contrary - seems to be only longint. So,
> you can't seek beyond 2.4gb, the counter just wraps
> into negative numbers. Even tried the 'relative' offset
> approach ... no good and a lot more counters to keep
> track of.
Yes, you said so, but I have not noticed this. I may do the experiment
the next time I get an empty hard disk and free time.
I use this call:
repeat
...
{$I-}write(Fout,BigData[RandomIndex]);{$I+}
gotresult:= ioresult;
until gotresult <> 0;
Each write writes a 1 GiB array of bytes, stored in RAM.
where:
const
shuflecount = 1024;
arraysize = 1023;
ChunkSz=1048576;
type
tCacho= array [1..ChunkSz] of byte;
var
RandomIndex, RandomizeIndex: integer;
BigData : array [1..shuflecount] of tCacho;
Fin, Fout: file of tCacho;
My notes say do not use blockread.BlockRead
An experiment would be to write each sector with its LBA number, then
use dd to verify.
>
> Had to make a 'C' "helper" because, with some flags
> and such, you CAN lseek64(). If you just wanna melt
> a disk then FPC is ok, but if you wanna SEE/search for
> what's ON the disk at the 3.345tb mark then you have
> to cheat.
>
> My experimental disk was an old UServer drive. There
> WERE some recognizable passwords and such WAY out
> in the diskspace (maybe the swap partition ?)
>
> As I discussed with Mr. Natural, wiping an old disk
> is considered "good practice". However literally
> writing zeros or whatever over a whole 4/8/12tb
> disk can involve DAYS. Physical destruction is
> quicker. You can disassemble and save the magnets
> and pretty platters OR use a cold-chisel ....
> (WD drives. just off center at about the 8 o-clock
> position) ...
>
> A *fairly* easy approach is to use gparted ... create
> a new partition table and then reformat EXT2. Now it's
> faster to reformat EXT3/4 but EXT2 does a LOT more
> work redoing of the disk to it's own special, and now
> rarely-used, way. No hope for the casual hacks after that ...
>
> SSDs, physically destroy - the wear-leveling scheme
> thwarts the usual overwrite methods.
>
> CD/DVD - five secs in an old microwave. Very artistic
> results too.
--
Cheers, Carlos.
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Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-02-18 17:39 +0100
Re: Zip list The Natural Philosopher <tnp@invalid.invalid> - 2023-02-19 11:10 +0000
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Re: Zip list "Andrei Z." <no-email@invalid.invalid> - 2023-02-24 07:58 +0300
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-25 00:15 -0500
Re: Zip list "Andrei Z." <no-email@invalid.invalid> - 2023-02-25 09:34 +0300
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-25 02:33 -0500
Re: Zip list The Natural Philosopher <tnp@invalid.invalid> - 2023-02-25 10:19 +0000
Re: Zip list Eric Pozharski <whynot@pozharski.name> - 2023-02-25 13:43 +0000
Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-02-25 12:04 +0100
Re: Zip list The Natural Philosopher <tnp@invalid.invalid> - 2023-02-25 10:00 +0000
Re: Zip list Andreas Kohlbach <ank@spamfence.net> - 2023-02-18 16:18 -0500
Re: Zip list The Natural Philosopher <tnp@invalid.invalid> - 2023-02-19 11:13 +0000
Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-02-19 12:48 +0100
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-25 00:51 -0500
Re: Zip list Rich <rich@example.invalid> - 2023-02-25 06:15 +0000
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-25 02:30 -0500
Re: Zip list The Natural Philosopher <tnp@invalid.invalid> - 2023-02-25 10:17 +0000
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-25 23:08 -0500
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Re: Zip list The Natural Philosopher <tnp@invalid.invalid> - 2023-02-25 10:09 +0000
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-26 00:12 -0500
Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-02-25 12:10 +0100
Re: Zip list "25A.I866" <25A.I866@noacba.net> - 2023-02-25 23:41 -0500
Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-02-26 20:22 +0100
Re: Zip list "28A.I873" <28A.I873@noabzba.net> - 2023-02-26 23:56 -0500
Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-02-27 19:26 +0100
Re: Zip list "28A.I873" <28A.I873@noabzba.net> - 2023-02-27 22:20 -0500
Re: Zip list Rich <rich@example.invalid> - 2023-02-28 15:21 +0000
Re: Zip list "Carlos E.R." <robin_listas@es.invalid> - 2023-03-01 23:23 +0100
Re: Zip list "28A.I873" <28A.I873@noabzba.net> - 2023-03-02 00:02 -0500
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Re: Zip list Eric Pozharski <whynot@pozharski.name> - 2023-02-18 14:55 +0000
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