I'm CaLendarW Blog

前幾日經 RSS 睇到個 post 講 maintainable, 睇完都有同感.

Maintainable is a value that can only be applied by someone who is familiar with the codebase. If that someone find it hard to work on the codebase, it is hard to maintain. If someone with no knowledge of a codebase find it hard to work with it, tough luck, but that doesn’t say anything about the maintainability of a code base.

A codebase is more than just a code sample, it is conventions, ways of doing things, overall architecture and a sense of how to do things.

Now, there is a separate value, related to how easy it is to bring someone up to speed on the codebase, but that does not relate directly to maintainability.

公司唔係 Software House, 有好多古舊既 code 都係無乜被設計過, 見到有好多 On Demand 加上去既 Feature, 同埋一大堆不段累積既雜 code, 經過很多不同 developer 世代經手後, 形成了 Anti-Pattern 中既 Lava flow.

公司既舊 code, 最難 maintenance 既話分係 multi-programming language, 可能因為 application-database 既關係, 老一輩寫開既大多都係 stored procedure, 除左 data filtering 之外, 很多簡單既 business logic 都 embed 左係入面, 就連 SELECT * FROM tblA 都會寫入 stored procedure, 除此之外, 舊 code 除左 C#, 仲有 Visual Basic, C++, J2ME, PHP, ASP.net 等等, 好難去用同一個 IDE 黎睇晒同一個 project 既野, 所以 maintainability 都幾困難. 不過, 近期新人多左, 公司都慢慢有了改變, 除左要些時間磨合之外, 公司都開始進步, 不似之前有點停滯不前既感覺.

軟件, 寫下來就要不段地維護及更新, 世界在變, 如果軟件不變, 那就會變得不合時宜, 所以維護性係一個十分重要既部份!!

Architecture is defined by the recommended practice as the fundamental organization of a system, embodied in its components, their relationships to each other and the environment, and the principles governing its design and evolution.

IEEE/ANSI

The software architecture of a program or computing system is the structure or structures of the system, which comprise software elements, the externally visible properties of those elements, and the relationships among them.

Bass et al. (2003)

[Software architecture goes] beyond the algorithms and data structures of the computation; designing and specifying the overall system structure emerges as a new kind of problem. Structural issues include gross organization and global control structure; protocols for communication, synchronization, and data access; assignment of functionality to design elements; physical distribution; composition of design elements; scaling and performance; and selection among design alternatives.

Garlan & Shaw (1993)

Enterprise Resource Planning 既定義 : “Integrated Information System”. 

阿 sir 話其實 ERP 呢個名係佢啱啱出果時係用放工業方面做計劃, 所以有 Planning 呢個字係中間, 而家既 ERP 已經同 BPR 一樣, 個名只係代表左原本既理念, 時至今日, 已經被其他人用於其他用途.

Project is “a temporary endeavor undertaken to create a unique product, service, or result”, which means it is temporary, require resources, unique purpose and it has business values.

大學之道：在明明德，在親民，在止於至善。知止而後有定；定而後能靜；靜而後能安；安而後能慮；慮而後能得。物有本末；事有終始。知所先後則近道矣。
古之欲明明德於天下者先治其國。欲治其國者先齊其家。欲齊其家者先修其身。欲修其身者先正其心。欲正其心者先誠其意。欲誠其意者先致其知。致知在格物。物格而後知至。知至而後意誠。意誠而後心正。心正而後身修。身修而後家齊。家齊而後國治。國治而後天下平。
自天子以至於庶人者是皆以修身為本。其本亂而末治者，否矣。其所厚者薄而其所薄者厚，未之有也。