A tale of Jitter

vbimport

#1

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.


#2

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)






#3

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)






#4

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)






#5

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)






#6

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?


#7

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:


#8

:bigsmile:

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


#9

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.


#10

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.


#11

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.




#12

while scan_continues
if jitter_value = too_extreme

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

That would do the trick…

:bigsmile:


#13

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!!*/
}
}