A tale of Jitter

I’ve noticed that my 716a gives different results in a Jitter scan than my 712a. Now this would not be generally disturbing because every drive is a bit different but there has also been some talk that the Jitter results from an 716a seem to be a bit weird in general. So I set out to do some testing.

The next four posts show scans of data and audio CDs burnt in both drives and scanned in both drives.

716a, TLA#0202, FW 1.07
Ritek Type 7, @48x,
DATA-Track

first two pictures show C1,2,U and Beta/Jitter scan in an 716a
second two pictures show C1,2,U and Beta/Jitter scan in an 712a (FW 1.07)





716a, TLA#0202, FW 1.07
Ritek Type 7, @48x,
AUDIO-Track

first two pictures show C1,2,U and Beta/Jitter scan in an 716a
second two pictures show C1,2,U and Beta/Jitter scan in an 712a (FW 1.07)





712a, FW 1.07
Ritek Type 7, @48x,
DATA-Track

first two pictures show C1,2,U and Beta/Jitter scan in an 712a
second two pictures show C1,2,U and Beta/Jitter scan in an 716a (FW 1.07)





712a, FW 1.07
Ritek Type 7, @48x,
AUDIO-Track

first two pictures show C1,2,U and Beta/Jitter scan in an 712a
second two pictures show C1,2,U and Beta/Jitter scan in an 716a (FW 1.07)





Result: 716a scans of DATA-Tracks have lots of spikes, but AUDIO-Tracks are more or less ‘regular’ whereas Jitter results of the 712a are always ‘regular’.

What do you think?

From http://www.plextools.com/info/versions.asp

Q-Check Beta/Jitter Test: The jitter values for DVD media are not always correct.

Don’t know about CD media, though…maybe it’s another Plextypo and they meant “CD” instead of DVD. :bigsmile:

:bigsmile:

Would be a funny bug that would report fine jitter on audio disks and scrap values on data disk.

Update:

About two weeks ago I hat a CD-USRW burned in the Premium that the 716a would not perform a BJ scan on (Media error). I forwarded this to Plextor.be with reference to this thread, our big CD-Results thread and the fact that a DVD-Jitter problem had been adressed recently in Plextools.

Today I got mail from Plextor asking fo additional info and the mention of forwarding this to engineering. Seems like I have conviced them there might be something wrong with the combination of Plextools the 716a and jitter results.

Good work hwp. I’ve seen the same thing here but never contacted Plextor about it, assuming they know their own product. Guess I was wrong.

This is not just a sample to sample variation either–I have 3 drives that all do the same thing, even with different TLA#'s, and it seemed to get worse at FW1.05 and beyond, if I’m not mistaken.

As of today, Pletor has released version 2.25 of Plextools. The changelog (among other things) lists:

> Q-Check Beta/Jitter Test: Improved Beta and Jitter results.

So i set out to do some more testing:

716a, TLA#0202, FW 1.08
Ritek Type 7, @48x,
DATA-Track

In comparison to Post #2 of this thread (specifically the first two attached scans), you’ll notice, that the Jitter spikes are now gone and that only the ‘base’ Jitter-line remains.

It looks like Plextor managed to squash one bug.

In conclusion this means that B/J-Scans with Plextools 2.24b in combination with an 716a are to be taken with a grain of salt, especially when it comes to Jitter values.



while scan_continues
if jitter_value = too_extreme

[INDENT]ignorevalue
plot previous_good_value
endif[/INDENT]
endwhile

That would do the trick…

:bigsmile:

That reminds me of this :bigsmile: :bigsmile: (sorry, OT):

Subject: *** TOP SECRET MICROSOFT CODE ***
Project: Version - Windows 95

Microsoft marketing strategy (MARKET.EXE):

#include
#include
#include /* Microsoft Network Connectivity library /
#include /
For the court of law */

#define say(x) lie(x)
#define computeruser ALL_WANT_TO_BUY_OUR_BUGWARE
#define next_year soon
#define the_product_is_ready_to_ship another_beta_version

void main()
{
if (latest_window_version>one_month_old)
{
if (there_are_still_bugs)
market(bugfix);
if (sales_drop_below_certain_point)
raise(RUMOURS_ABOUT_A_blank_BUGLESS_VERSION);
}
while(everyone_chats_about_blank_version)
{
make_false_promise(it_will_be_multitasking); /* Standard Call, in
lie.h /
if (rumours_grow_wilder)
make_false_promise(it_will_be_plug_n_play);
if (rumours_grow_even_wilder)
{
market_time=ripe;
say(“It will be ready in one month);
order(programmers, stop_fixing_bugs_in_old_version);
order(programmers, start_brainstorm_about_blank_version);
order(marketingstaff, permission_to_spread_nonsense);
vapourware=TRUE;
break;
}
}
switch (nasty_questions_of_the_worldpress)
{
case WHEN_WILL_IT_BE_READY:
say(“It will be ready in”, today+30_days,” we’re just testing");
break;
case WILL_THIS_PLUG_AND_PLAY_THING_WORK:
say(“Yes it will work”);
ask(programmers, why_does_it_not_work);
pretend(there_is_no_problem);
break;
case WHAT_ARE_MINIMAL_HARDWARE_REQUIREMENTS:
say(“It will run on a 8086 with lightning speed due to”
" the 32 bits architecture");
inform(INTEL, “Pentium sales will rise skyhigh”);
inform(SAMSUNG, “Start a new memorychip plant”
“'cos all those customers will need at least 32 megs”);
inform(QUANTUM, “Thanks to our fatware your sales will triple”);
get_big_bonus(INTEL, SAMSUNG, QUANTUM);
break;
case DOES_MICROSOFT_GET_TOO_MUCH_INFLUENCE:
say(“Oh no, we are just here to make a better world for
everyone”);
register(journalist, Big_Bill_Book);
when(time_is_ripe)
{
arrest(journalist);
brainwash(journalist);
when(journalist_says_windows_95_is_bugfree)
{
order(journalist, “write a nice objective article”);
release (journalist);
}
}
break;
}
while (vapourware)
{
introduction_date++; /
Delay /
if (no_one_believes_anymore_there_will_be_a_release)
break;
say(“It will be ready in”,today+ONE_MONTH);
}
release(beta_version)
while (everyone_is_dumb_enough_to_buy_our_bugware)
{
bills_bank_account += 150
megabucks;
release(new_and_even_better_beta_version);
introduce(more_memory_requirements);
if (customers_report_installation_problems)
{
say(“that is a hardware problem, not a software problem”);
if (smart_customer_says_but_you_promised_plug_and_play)
{
ignore(customer);
order(microsoft_intelligence_agency, “Keep an eye on this
bastard”);
}
}
if ( bills_bank_account>skyhigh && marriage>two_years )
{
divorce(woman_that_was_beatifull_when_I_married_her);
wave(dollars, at_lusty_chicks);
marry(young_blond_virgin_with_big_boobies);
devirginize(young_blond_virgin_with_big_boobies);
if (boobies_start_to_hang)

    dump(young_blond_virgin_with_big_boobies);
}
if (there_is_another_company)
{
  steal(their_ideas);
  accuse(compagny, stealing_our_ideas);
  hire(a_lot_of_lawyers); /* in process.h */
  wait(until_other_company_cannot_afford_another_lawsuit);
  buy_out(other_company);
}

}
/* Now everyone realizes that we sell bugware and they are all angry at
us */
order(plastic_surgeon, make_bill_look_like_poor_bastard);
buy(nice_little_island); hire(harem);
laugh_at(everyone,
for_having_the_patience_year_after_year_for_another_unfinished_version);
}

void bugfix(void)
{
charge (a_lot_of_money)
if (customer_says_he_does_not_want_to_pay_for_bugfix)
say(“It is not a bugfix but a new version”);
if (still_complaints)
{
ignore(customer);
register(customer, big_Bill_book);
/* We’ll get him when everyone uses Billware!!*/
}
}