Post on 11-Jun-2018
The Things I Thought I’d Never Do
Sonesh SuranaI290: Designing Rural Computing Applications
Guest LectureNovember 4, 2008
Timeline
Aug 2004: 1 day
Jan 2005:
25 days
June 2005:
24 days
Aug 2005:
21 days
Dec 2005:
37 days
Feb 2006:
6 days
Oct 2006:
20 days
Jan 2008:
12 days
20041 day
2005107 days
200626 days
200812 days
Total146 days
“So then we put the separate modem at chimney now the link has been up it means , in Theni router-3 we put the ath1 card and it is focusing the new separate modem at chimney.
We have pointed out one think ie we put the new wireless card in the existing modem(suppose we put the ath1 in , Theni router-3 , already it connected to SBS through ath0) the link quality will be down).”
23
Poor Quality Power
Spikes and Swells:
• Lost 50 power adapters
• Burned 30 PoE ports
Low Voltages:
• Incomplete boots
• HW watchdog fails
Frequent Fluctuations:
• CF corruptions
• Battery Damage
Volta
ge R
ange
Number of Instances seen over 6 weeks
24
What about UPS?
“Affordable” UPS systems ($300) are of standby-typePrimary source is gridSecondary source is batteryGood quality power supplied only during outage!
Real Cost of Power
Assume 7W
Monthly CostsGrid: $0.25
UPS + Battery: $6.08 (24X more!!)
50W Panel + Controller + Battery: $8.24
25
27
Operational Results
Equipment Supply
Installation
Management
Maintenance
TIER, UC Berkeley
Aravind
Local Vendor
Jan’06 – Jun’06
Migration at Aravind
2007: 5 more clinic links
Jun’07 – Dec’07Jul’06 – Dec’06 Jan’07 – Jun’07
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Jan-
06
Feb-
06
Mar
-06
Apr
-06
May
-06
Jun-
06
Jul-0
6
Aug
-06
Sep
-06
Oct
-06
Nov
-06
Dec
-06
Jan-
07
Feb-
07
Mar
-07
Apr
-07
May
-07
Jun-
07
Jul-0
7
Aug
-07
Sep
-07
Oct
-07
Nov
-07
Dec
-07
Jan-
08
Feb-
08
Mar
-08
Apr
-08
May
-08
Jun-
08
Jul-0
8
Aug
-08
Sep
-08
Kallidakurchi
Srivaikundam
Sholavandan
Tirupovanam
Alanganallur
Andipatti
Periyakulum
Chinnamanur
Bodi
Ambasamudram
Num
ber of Patients
Patient Throughput
90,000 patients screened; vision restored for 15,858
Time in Months (Jan 2006 to September 2008)
Thank You!