Tolerable Flaw

How tolerable the flaw is ?

a)
In the early 1999, Ericsson discovered a flaw inside their mobile phone during the quality assurance testing. The flaw was caused by the embedded software inside the chip that generated particular radio output signal. The flaw was somehow related to the specific digit that was being entered into the keypad. The flaw occasionally cause the radio signaled "3" when keypad "2" was entered.

Further test and analysis had not discovered the cause of the flaw. Meanwhile, the product had to be launched to the public within the few weeks. The public, which had wait anxiously for this product, had ordered $25 millions for the product’s initial release. Total sales of $120 millions were expected to come within the full year.

The developer’s team could not fix the problem yet, but they were able to characterize the flaw. Apparently, the flaw was quite random, and would occur on average once in approximately 200 times that a "2" was entered.

It was estimated that for 7-digit telephone numbers, the overall average occurrence of the wrong telephone number being signaled out was around 1 in 250. Furthermore, if the same number was immediately re-keyed, the chance of the fault being repeated again appears to be negligible.

However, there were some "worse cases", for example the number 222 2222 would be wrongly out signaled on the average around 1 in 30 times.

If you were CTO (Chief Technology Officer) for this product, what would you do ? Discuss the various factors and arguments you would consider !

b)
Sewaktu gw bekerja untuk iNeo, gw pernah mengalami masalah dengan keypad produk yang kami kembangkan. Entah kenapa jika keypad "2" ditekan, muncul angka "3" di LCD display (bisa ditanyakan ke para saksi hidup, kl ga percaya). Waktu itu gw sempat berdebat dengan MM mengenai perlu tidaknya bug ini diperbaiki sebelum produk diserahkan ke customer.

Dari sisiku, bug semacam ini tidak terlalu mengganggu, karena user bisa menghapus angka "3" dan menekan angka "2" lagi (kecuali di bagian password, karena yang muncul di layar hanya "*"). Tapi, kl aku bilang, begitu user/password mereka tidak diterima, user pasti akan mengulang input user/password yang sama. MM berpendapat bahwa ada kemungkinan user tersebut malah keliru memasukkan user/password orang lain jika bug ini tidak diperbaiki.

Gw ga secanggih Ericson yang bisa mengukur peluang kejadian fault ini. Tapi seingat gw fault ini cuma muncul kalo keypad "2"-nya sudah ditekan kurang lebih 50-kali ke atas (walaupun ada kejadian faultnya muncul setelah angka "2"-nya ditekan 10-kali).

Kl lu di posisi gw, apa yang lu lakuin ?

Kejadian (a) adalah materi diskusi kursus yang gw ikuti di Penang-Malaysia. Kejadian (b) adalah kejadian nyata yang gw sendiri pernah alami. Dua-duanya punya andil terhadap sisi lain proses desain yang jarang ditulis di buku-buku kuliah.

So, any comments ?

** Apapun spek kalian, sisakan space untuk toleransi kesalahan.




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