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ZX Spectrum 48K: Press Play On Tape… (aka yemişim Enterprise Computing'i!)

12 Oct

Gece yarısından sonra nostalji. Bir anda aklıma düşüverdi. Wikipedia sağolsun, çocukluğum ve ilk gençliğim. Ve sonra…

Most Spectrum software was originally distributed on audio cassette tapes. The software was encoded on tape as a sequence of pulses that may sound similar to the sounds of a modern day modem. Since ZX Spectrum had only a rudimentary tape interface, data was recorded using an unusually simple and very reliable modulation, similar to pulse-width modulation but without a constant clock rate. Pulses of different widths (durations) represent 0s and 1s. A “zero” is represented by a ~244 ?s pulse followed by a gap of the same duration (855 clock ticks each at 3.5 MHz) for a total ~489 ?s;[28] “one” is twice as long, totaling ~977 ?s. This allows for 1023 “ones” or 2047 “zeros” to be recorded per second. Assuming an even proportion of each, the resulting average speed was ~1365 bit/s. Higher speeds were possible using custom machine code loaders instead of the ROM routines.

Theoretically, a standard 48K program would take about 5 minutes to load: 49152 bytes × 8 = 393216 bits; 393216 bits / 1350 baud ? 300 seconds = 5 minutes. In reality, however, a 48K program usually took between 3?4 minutes to load (because of different number of 0s and 1s encoded using pulse-width modulation), and 128K programs could take 12 or more minutes to load. Experienced users could often tell the type of a file, e.g. machine code, BASIC program, or screen image, from the way it sounded on the tape.

Doğru mu? Doğru. Evet, hatırlıyorum. Ben de o kullanıcılardan biri idim.

Bu kadarla kalsa iyi, dahası da var:

One unusual software distribution method were radio or television shows in e.g. Belgrade (Ventilator 202), Poland, Czechoslovakia, Romania or Brazil, where the host would describe a program, instruct the audience to connect a cassette tape recorder to the radio or TV and then broadcast the program over the airwaves in audio format.

Another unusual method which was used by some magazines were 7″ 33? rpm “flexidisc” records, not the hard vinyl ones, which could be played on a standard record player. These disks were known as “floppy ROMs”.

Birader eski bir pikabın var mı? Yok hayır, benim emektar Spectrum’a bağlayacağım da! 😉 Televizyon anteni, ha o da olur!

C64çüler ve Amigacılar övünedursun, 1980’lerin ortasında onlara kıyasla gerçekten kısıtlı ve çok çok az imkana sahip olan bilgisayar ZX Spectrum idi ve asıl maharet bu kadar kısıtlı bir aletin üzerinde onca programı geliştirmek ve diğer platformlar için yazılmış programları bu alete taşımak idi.

Gecenin bir köründe MS Windows Server 2003 üzerinde SQL Server 2005, onun üzerinde NHibernate, Castle Project, Castle ActiveRecord, ASP.NET ve bunları birleştiren Object DataSource, onun üzerinde AJAX için Atlas.NET çatısı, vs. birbiri üstüne binen onca katman ile uğraşırken 48 KB üzerinde kod yazdığım, oyun oynadığım ve müthiş bir heyecanla, kardeşimle birlikte eğlendiğimiz günleri hatırlıyorum.

Bu satırları okurken benzer hissiyatı paylaşan en az birkaç kişi daha olduğu düşüncesi ile geceyi tüketmeye devam ediyorum…

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Posted by on October 12, 2006 in General

 

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