[mtnagel]

I have 42 SL's (Series Links) currently and I'm sure I will have a few more with the new shows coming up in January, so I'm afraid that I will soon hit the 50 SL limit and get to a point where I have to make a decision instead of just being able to add what I want.

Does anyone (especially Earl) know why this limit is there? I see that you (Earl) posted previously that you had no idea why there was the limit. I wonder if that's still the case? Anyway you can ask your contacts?

Can anyone else speculate why? Could it possibly be a hardware limitation where the system might slow down or become unstable (even more so) if you had more than 50?

I see the R15 has the limit too so I fear that we'll never see the limit go away.

 

[mtnagel]

I guess the lack of response means I watch too much tv.

 

[Earl Bonovich]

It is Saturday, on a Holiday weekend... So the forum isn't "hoping" like it normally does...

I have never been given a reason on why, other then that is what they did.

 

[Tom Robertson]

ALN(BIBE) strategy. (Arbitrarily Large Number (But Isn't Big Enough))

Tom

 

[houskamp]

cause somebody sitting at a desk (problably not an engineer) decided that was all anybody would need...
noone will ever need more than 512k of memory.. bill gates...:lol:

 

[lwilli201]

It probably is a memory thing. There probably is only enough memory for 50 Series links allocated to this function.

 

[Tom Robertson]

cause somebody sitting at a desk (problably not an engineer) decided that was all anybody would need...
noone will ever need more than 512k of memory.. bill gates...:lol:

In the mid '60s, IIRC, IBM released the first model of the IBM 360 with 16k of memory as a default. Two weeks later, they changed that to 32k.

In 1980, IBM released their PC with 16k of memory. And yes, two weeks later they increased it to 32k.

Some mistakes are born, others have mistakes thrust upon them again and again cuz they don't learn from history.

Have a Happy New Year,
Tom

 

[mtnagel]

It just seems weird to arbitrarily pick a limit when no limit should be necessary (unless it's truly a memory issue). You'd think they'd just copy TiVo as much as possible. I'm sure TiVo doesn't have a patent on their non-limit to Season Passes.

I haven't called to complain to D* about the HR20 (haven't really had any major issues), but I think I may have to on this one.

 

[Tom Robertson]

It just seems weird to arbitrarily pick a limit when no limit should be necessary (unless it's truly a memory issue). You'd think they'd just copy TiVo as much as possible. I'm sure TiVo doesn't have a patent on their non-limit to Season Passes.

I haven't called to complain to D* about the HR20 (haven't really had any major issues), but I think I may have to on this one.

Now you've got me wondering. I'm going to have to look up the patents Tivo does own. :lol: :lol:

I'm sure memory plays a bit part in all this, the more you have the more processing time the HR20 will take each time it loops thru the lists of SL, Todo, Guide updates, and the purging cycle.

Happy New Year,
Tom

 

[mtnagel]

So I wonder if they did testing on different limits? Does 55 cause instability? How come my TiVo is just as slow as the day I got it

 

[Tom Robertson]

Now the poor Tivo has many good things within, but it had one nasty flaw hidden under the covers--a very unscalable database. It probably worked great when there where only 5 local channels, but on a cable system with 68 it started to become marginal, I'm guessing. Then when Directv hit, with 300+ channels of data, the db showed its true flaws. So the Tivo dudes and dudettes had to tweak the db heavily somewhere between 3.5 and 6.x. (I don't know if it was in the SA 4.0 or 5.0 versions.) Its better, but still hampered by how it handles that much relational data.

Happy New Year,
Tom

 

[marksman]

That sucks. One of my TiVos has like 140 season passes on it. I like to rack them up.

50 is way too small for my habits.

 

[Tom Robertson]

That sucks. One of my TiVos has like 140 season passes on it. I like to rack them up.

50 is way too small for my habits.

Wow! If I may ask, for my education, are they mostly wishlists, season passes for current shows, or something I'm missing? I bet your list would make an awesome test case!

Happy New Year,
Tom

 

[Wolffpack]

I'm sure memory plays a bit part in all this, the more you have the more processing time the HR20 will take each time it loops thru the lists of SL, Todo, Guide updates, and the purging cycle.

Series-2 DTivo = 42MB Memory
HR10 = 92MB Memory
R15 = 64MB Memory
HR20 = ???

So if Tivos have an unlimited number of SPs and the 50SL limit of the R15/HR20 are due to lack of memory, then one would have to question the designers of the R15/HR20 and their reason to rely so heavily on everything being memory resident.

 

[houskamp]

Series-2 DTivo = 42MB Memory
HR10 = 92MB Memory
R15 = 64MB Memory
HR20 = ???

So if Tivos have an unlimited number of SPs and the 50SL limit of the R15/HR20 are due to lack of memory, then one would have to question the designers of the R15/HR20 and their reason to rely so heavily on everything being memory resident.

simple answer=speed

 

[Tom Robertson]

Wolffpack,

Sorry, let me clarify: I'm still firmly believing in ALN (Arbitrarily Large Number) as how the limit was set at 50. I completely agree with your memory analysis; I tried to answer a previous post as to how more SL means more memory and processing. I should have also stated that 50 is still way too low for a well designed architecture cuz the newer boxes likely have faster CPUs as well as more memory.

In short: 50 too low.

BTW, did you see the report from awhile ago where someone, was it milominderbender?, who talked to a D* person about many topics? One of the questions was "why not store guide between reboots" and the answer was telling (in many ways). Something like needing to process 3200 channels of locals which has to be done in memory (but doesn't address why my 30 channels can't be stored to disk...) It does help explain how D* is using that much memory.

Happy New Year,
Tom

 

[Wolffpack]

It's just that some of the reasoning doesn't make sense when Tivos can do the same job with SPs and guide data stored on disk.

Regarding the 3200 local channels, is that indicating that the guide data for every SD and HD local channel is stored in everyone's unit? Why would that be? SD locals don't work that way.

 

[carrot]

50 is way too low.

This PVR has just been in folks homes for an average of just a few months and that barely covers one “season” of TV schedules. As the TV seasons revolve some SL’s will be dormant until next year and many more will be added. With the current 50 limit you are forced to delete dormant SL’s and miss the out of season repeats or when the new series returns.

This problem is going to get much worse and even those with 20 SL’s now will hit the limit long before a year.

 

[Tom Robertson]

It's just that some of the reasoning doesn't make sense when Tivos can do the same job with SPs and guide data stored on disk.

Regarding the 3200 local channels, is that indicating that the guide data for every SD and HD local channel is stored in everyone's unit? Why would that be? SD locals don't work that way.

Yupper. Storing data to disk isn't that hard...(obviously, so why don't they, even if its just an occasional snapshot?)

IIRC the comment re: 3200 channels might mean they only store all that data only while they process out to another area of memory the guide data for CIR. But I'm guessing here.

Ah well, one thing at a time, I guess
Tom

 

[theantidote]

I don't know how D* codes their DVR software but I think the Tivo will create a cron job for a recording and then forget about it. I'm assuming that the D* way is different because it tends to miss recordings. I guess they just hold a record function in memory until a specific time? I'm not sure how it would work for them.